SeaCities: Urban Tactics for Sea-Level Rise
 9811587477, 9789811587474

Table of contents :
Foreword by Prof. Andrew T. Smith
Preface
Acknowledgements
Contents
Editors and Contributors
Re-Building Coastal Cities: 20 Tactics to Take Advantage of Sea-Level Rise
1 Sea-Level Rise (SLR)
2 Urban Flooding
3 Re-Building Coastal Cities
4 Risks as Opportunities
5 Urban Elements
6 Urban Adaptation Models for SLR
7 20 Tactics
8 Discussion
References
Design Strategies for Coastal Adaptation Urban Speculation in Palm Beach, Gold Coast—Australia
1 Introduction: Study Drivers
2 Design Strategies
3 Project Exegesis
4 Conclusion
References
When It’s Time to Let Go: Re-Imagining Coastal Urban Living in the Face of Rising Seas
1 Introduction
2 Living Harmoniously with Water
3 Managed Retreat and Resettlement
3.1 Australia
3.2 The United States
3.3 The Netherlands
3.4 The United Kingdom
3.5 New Zealand
4 Opportunities: Re-Imagining the Future of Sea Cities in a Changing Climate
5 Conclusions
References
Lo-TEK: Underwater and Intertidal Nature-Based Technologies
1 Changing Grounds
2 Lo-TEK
3 Adaptation Pathways
3.1 Defend/Protect
3.2 Surrender/Accommodate
3.3 Offend/Advance
3.4 Retreat
4 Futures
4.1 Hybridizing Ecosystem-Based Approach is the Best Scenario for Infrastructural Resilience
5 Conclusion—Further Discussion
References
Exploiting Sediment- and Morpho-Dynamics in Coastal Adaptation Strategies to Sea-Level Rise: A Case Study of the Vietnamese Mekong Delta
1 Introduction
2 Overview of Geomorphology Along the Coast of the Mekong Delta
2.1 Sediment Accumulation and Formation of the Mekong Delta
2.2 Subaqueous Delta and Longshore Sediment Transport
2.3 Shoreline Erosion and Sediment Supply Reduction
3 Lessons Learned from Erosion Reduction and Sedimentation Stimulation by Using Bamboo Breakwater Along the East Coast of the Mekong Delta
3.1 Introduction
3.2 Application of T-shaped Bamboo Fences and Mangrove Rehabilitation
4 A Potential Strategy of Accelerated Sedimentation for New Protective/Productive Landscape on the Subaqueous Delta Platform of the Mekong Delta
4.1 Introduction
4.2 Technical Considerations
4.3 The Threat of Sediment Supply Deficit
4.4 Potential Application
5 Conclusion
References
Water as Leverage: Design Studies for Khulna, Chennai and Semarang
1 Introduction
2 Water Management Challenges in Urbanised Areas
2.1 Coastal Towns and the Delta Paradigm
2.2 The ‘Water as Leverage for Resilient Cities Asia’ Project
2.3 Water and Climate Related Challenges in the Three WAL-Cities
3 Water as Leverage (WAL) Design Projects
3.1 Khulna as a Water Inclusive Enclave
4 City of 1000 Tanks, Chennai
4.1 Multidisciplinary Team
4.2 Challenges and Opportunities
4.3 Developed Vision/Strategy
4.4 Interventions
4.5 Cascading Semarang
5 Conclusions: Reflection on Design Projects
5.1 More Balanced Water Cycles
5.2 Aiming for Additional Benefits
5.3 Need for a Coordinated Implementation
References
Some Medical Issues Related to Human-Water Interaction: A Brief Introduction
1 Introduction
2 General Aspects Related to Sanitation of Water
3 Water-Borne Disease: Recreational Water Exposure and Food Poisoning
3.1 Enterotoxigenic Escherichia Coli (ETEC) Food Poisoning
3.2 Enterohemorrhagic Escherichia Coli (EHEC) Serotype O157:H7 Food Poisoning
3.3 Vibrio Cholera Food Poisoning
4 Viral Gastroenteritis
5 Giardia Lamblia
6 Seafood Toxicity and Fish-Related Histamine Toxicity-Scombroid Syndrome
7 Ciguatera Toxicity
8 Other Seafood Poisonings
9 Tetrodotoxin Poisoning
10 Heavy Metals Toxicities
11 Arsenic Poisoning
12 Discussion and Conclusions
References
The Relation Between Coastal Flood Risk and Ecosystem Services Affecting Coastal Tourism: A Review of Recent Assessments
1 Introduction
2 Research Methodology
2.1 Research Strategy and Inclusion Criteria
2.2 Classification Criteria
3 Results
3.1 Overview Analysis
3.2 Emergent Theme: Coastal Floods
3.3 Emergent Theme: Coastal Ecosystem Services
3.4 Emergent Theme: Coastal Tourism
4 Discussion
5 Conclusion
Appendix
References
Flood Pulse Design Principles—A Time-Based Approach to Urban Flooding
1 Introduction
2 Temporal Correlations in Wetland Ecosystems
2.1 Infrastructure—Protection and Establishment
2.2 Debris—Management Strategy
2.3 Productivity—Diversity and Resilience
3 Speculation and Examples of Applied Temporal Correlations in Urban Contexts
3.1 Infrastructure—Growth and Symbiosis
3.2 Debris—Lifespan and Functionality
3.3 Productivity—Diversity Types
4 Discussion
References
A Comparison Between Alternative Relocation Options for the Pacific Islands Based on a Human-Centred Approach
1 Introduction
2 Pacific Islands’ Response to Climate Change
2.1 Geomorphological Characteristics and the Anthropogenic Pressures
2.2 The Impact of Sea Level Rise and Flood on Food Production and Freshwater Availability
2.3 Current Adaptation Strategies
2.4 The Cases of Kiribati, Fiji, and Vanuatu
3 Human-Centred Approach and the Notion of Islandness
3.1 Psychological, Sociological, and Physiological Impacts
3.2 Cultural Disagreements
3.3 Global Agreements for Pacific Islands
3.4 Funds
3.5 Efficient Relocation Criteria
4 Relocation Options
4.1 Expansion
5 Conclusion—Further Discussion
References
Modelling of SeaCities: Why, What and How to Model
1 WHY Modelling of SeaCities
2 WHAT Modelling in SeaCities?
3 HOW Modelling? Modelling Categories
3.1 Model Choice Based on Inputs
3.2 Model Choice Based on Outputs
3.3 System Thinking and Integrated Approaches
4 Case Studies
4.1 A Hybrid GIS-System Dynamics Approach to Assess Vulnerability to Sea Level Rise
4.2 A Spatial BN Approach to Evaluate Future Coastal Erosion of a Pacific Island
5 Conclusions
References
Overlapping Worlds: An Indigenous Jurisprudential Approach to SeaCities
1 The Winding Path of Commentary
2 Turning to a Story—Measurement and Speed
3 Straight Lines and Winding Paths
4 Wilful Ethics
5 Major Cultural Shifts
6 The Vikings and Ragnarok
7 Conclusion
References

Citation preview

Cities Research Series

Joerg Baumeister Edoardo Bertone Paul Burton Editors

SeaCities Urban Tactics for Sea-Level Rise

Cities Research Series Series Editor Paul Burton, Gold Coast Campus, Griffith Univ, Urban Research Program, Southport, QLD, Australia

This book series brings together researchers, professionals and policy makers in the area of urban development and publishes recent advances in the field. It addresses issues to understand and meet urban challenges and make (future) cities sustainable and better places to live. The series covers the following topics, but not limited to: • • • • • • •

Transport policy and behaviour Architecture, architectural science and construction engineering Urban planning, urban design and housing Infrastructure planning and management Complex systems and cities Urban and regional governance Smart and digital technologies

More information about this series at http://www.springer.com/series/16474

Joerg Baumeister Edoardo Bertone Paul Burton •



Editors

SeaCities Urban Tactics for Sea-Level Rise

123

Editors Joerg Baumeister Gold Coast Campus Cities Research Institute Southport, QLD, Australia

Edoardo Bertone Gold Coast Campus Cities Research Institute Southport, QLD, Australia

Paul Burton Gold Coast Campus Cities Research Institute Southport, QLD, Australia

ISSN 2662-4842 ISSN 2662-4850 (electronic) Cities Research Series ISBN 978-981-15-8747-4 ISBN 978-981-15-8748-1 (eBook) https://doi.org/10.1007/978-981-15-8748-1 © Springer Nature Singapore Pte Ltd. 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Singapore Pte Ltd. The registered company address is: 152 Beach Road, #21-01/04 Gateway East, Singapore 189721, Singapore

This book is dedicated to all the members of the Griffith SeaCities group for your contributions to this book and to your family and friends who supported you in this project.

Foreword by Prof. Andrew T. Smith

Coastal cities will have to change in the future. The higher the predictions of sea-level rise and its associated impacts, the sooner this change will have to occur. While some see the complexity of cities as a hindrance, we see the opposite: complexity can be helpful in exploring cost-effective opportunities to redesign and rebuild our coastal cities. The book is intended to test this assumption. It is the result of collaboration between like-minded academic and built environment professionals who came together at the first SeaCities Symposium, held at Griffith University’s Gold Coast campus from 2–4 March 2020. We believe the SeaCities initiative provides an excellent platform for urban experiments designed in response to the challenges associated with sea-level rise. As part of the Cities Research Institute, one of the largest groups of urban researchers in Australia, and in partnership with a network of researchers from around the world, including at Columbia and Delft University and with industry

SeaCities Symposium, 2 March 2020, Griffith University

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Foreword by Prof. Andrew T. Smith

partners like DeFacto, we are well placed to draw on a wide range of practical expertise and critical insight. This enables a truly interdisciplinary approach including the perspectives of architecture, urban planning and governance, systems engineering, as well as cultural ecology, human health, physics, oceanography and indigenous jurisprudence. This book is a first milestone of the SeaCities research group which we hope will lay the foundation for a continuing critical dialogue about how we might live more securely and sustainably in coastal settings. If you would like to join us in this dialogue, we welcome you contacting any of the authors or editors. Yours Sincerely

Prof. Andrew T. Smith PVC Science Griffith University Brisbane, Australia

Preface

Griffith University was created to be a different kind of university: challenging conventions through interdisciplinary research and teaching to create bold new visions of the future and pioneering solutions to real-world problems. The SeaCities research group is a new example of this pioneering spirit. According to the World Bank, three billion of the global population live in coastal communities. Over 400 million people around the world, and over one million people in Australia live less than five metres above sea level. With predicted rises in sea level, people living in these coastal settlements will experience many detrimental effects, including loss of land, the impacts of more intense storm surges, deterioration of urban and natural environments, infrastructure vulnerabilities, human health risks, food insecurity and, as a consequence, profound climate-related existential threats. Developing and applying new digital and physical models in combination with traditional research methods and adaptable design strategies is a key feature of the methodological innovations pioneered by members of the SeaCities group. This holistic research approach—that spans and includes the disciplines of engineering, architecture and urban design, urban and regional planning and other environmental sciences—enables researchers in the group to develop new approaches to building with and for nature, to create ecosystem-based developments on land and sea that respond to the challenges faced by coastal communities in an adaptive and compatible fashion. The transition from terrestrial to amphibious to aquatic developments creates exciting design opportunities that can relieve land-based population pressures and foster innovative development solutions. Furthermore, it shifts the focus of research and its application from defining and managing increasing risks for coastal communities towards the exploration and development of novel design, engineering and infrastructure solutions. These can seek to blend and merge the sea and land environments in a productive and sustainable fashion. This book provides a critical overview of different approaches to dealing with the challenges faced by and opportunities available to contemporary coastal cities. Insightful as well as provocative, this book is to be commended to anyone ix

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interested in exploring and developing the idea of SeaCities. As well as reporting on research carried out by members of the SeaCities group, it also includes contributions from some of the leading researchers and practitioners in this field from around the world. Southport, Australia

Joerg Baumeister Edoardo Bertone Paul Burton

Acknowledgements

The editors are thankful to all the chapter authors for their outstanding contributions to this book. The editors would also like to thank all the chapters reviewers for dedicating their valuable time to improving the quality of this book. Finally, we would like to thank the City of Gold Coast and Griffith University for their support in helping organise and host the SeaCities Symposium in March 2020 and especially to Diane McDonald of the Cities Research Institute for her patience and logistical expertise. We are also grateful to Professor Carolyn Evans, Vice Chancellor and President of Griffith University; Professor Andrew T. Smith, Pro-Vice Chancellor of Griffith Sciences; and Councillor Tom Tate, Mayor of the Gold Coast for supporting and helping launch the SeaCities Research Initiative and the Symposium which made a significant contribution to the conceptualisation and delivery of this book.

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Contents

Re-Building Coastal Cities: 20 Tactics to Take Advantage of Sea-Level Rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Joerg Baumeister

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Design Strategies for Coastal Adaptation Urban Speculation in Palm Beach, Gold Coast—Australia . . . . . . . . . . . . . . . . . . . . . . . . . . Cecilia Bischeri

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When It’s Time to Let Go: Re-Imagining Coastal Urban Living in the Face of Rising Seas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Elnaz Torabi and Aysin Dedekorkut-Howes

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Lo-TEK: Underwater and Intertidal Nature-Based Technologies . . . . . . Julia Watson, Despina Linaraki, and Avery Robertson

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Exploiting Sediment- and Morpho-Dynamics in Coastal Adaptation Strategies to Sea-Level Rise: A Case Study of the Vietnamese Mekong Delta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Thang Viet Nguyen, Kelly Shannon, and Bruno De Meulder Water as Leverage: Design Studies for Khulna, Chennai and Semarang . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133 Anne Loes Nillesen, Mona zum Felde, Eva Pfannes, Han Meyer, and Olv Klijn Some Medical Issues Related to Human-Water Interaction: A Brief Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Eugen Bogdan Petcu The Relation Between Coastal Flood Risk and Ecosystem Services Affecting Coastal Tourism: A Review of Recent Assessments . . . . . . . . . 191 Carlotta Quagliolo, Alessandro Pezzoli, Elena Comino, and Marco Bagliani

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Flood Pulse Design Principles—A Time-Based Approach to Urban Flooding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217 Ioana Corina Giurgiu A Comparison Between Alternative Relocation Options for the Pacific Islands Based on a Human-Centred Approach . . . . . . . . . . . . . . . . . . . 253 Despina Linaraki Modelling of SeaCities: Why, What and How to Model . . . . . . . . . . . . . 271 Edoardo Bertone and Oz Sahin Overlapping Worlds: An Indigenous Jurisprudential Approach to SeaCities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 C. F. Black

Editors and Contributors

About the Editors Prof. Dr.-Ing. Joerg Baumeister has been a practitioner, educator, researcher and consultant for Architecture and Urban Design for more than 20 years throughout Europe, Africa, the Arabian Peninsula, Asia and Australia. As University educator with passion for “his” students, he tries to fuse research, higher education and implementation in order to create feedback loops to evolve the fields of Urban Design and Architecture. Joerg founded in 2019 the “SeaCities” research laboratory (SeaCities.org) at the Cities Research Institute, Griffith University to develop water-adapted cities and floating structures. He is consulting governmental institutions on the federal, state and regional level as well as NGOs and private industry leaders to apply his current research interests which comprise SeaCities, ecological cities, affordable housing in serial building technology and design innovation through creative thinking. He is an award-winning Architect and Urban Designer and continues to be an enthusiastic speaker at international conferences. Joerg is DAAD Ambassador and Scientist for Future.

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Dr. Edoardo Bertone is a researcher with a civil engineering background, and he has a current research focus on data-driven modelling, Bayesian network and system dynamics modelling applied to the water resources management, water treatment optimisation, water-energy nexus, sustainable cities, environmental health and climate change adaptation fields. He completed his Ph.D. in water resources engineering in 2015, and he is currently a lecturer at Griffith University. He collaborates with several large Australian water utilities, Government departments and city councils, and he is a member of the SeaCities group under Griffith’s Cities Research Institute. Paul Burton is Professor of Urban Management and Planning and Director of the Cities Research Institute at Griffith University. Having trained and worked in London as a town planner, he joined the School for Advanced Urban Studies at the University of Bristol, UK, to carry out research for his Ph.D. on the redevelopment of London’s docklands. Over the next three decades, he led and contributed to research projects on living conditions in European cities, homelessness among young people, the links between housing and labour markets as well as a range of national urban policy evaluations. Since moving to Australia in 2007, Paul’s research has focused on multi-level governance in metropolitan settings, new techniques of community engagement and the professional lives of planners. He is the Series Editor for the Springer Cities Series and an active member of the Planning Institute of Australia.

Contributors Marco Bagliani University of Torino, Turin, Italy Joerg Baumeister Cities Research Institute, Griffith University, Brisbane, Australia Edoardo Bertone School of Engineering and Built Environment, Cities Research Institute, Australian Rivers Institute, Griffith University, Brisbane, QLD, Australia

Editors and Contributors

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Cecilia Bischeri Architecture and Design, School of Engineering and Built Environment, Gold Coast Campus, Griffith University, Brisbane, QLD, Australia C. F. Black Griffith Centre for Coastal Management, Cities Research Institute, Griffith University, Brisbane, QLD, Australia Elena Comino Politecnico di Torino, Turin, Italy Bruno De Meulder KU Leuven, Leuven, Belgium Aysin Dedekorkut-Howes Griffith University, Gold Coast, Australia Ioana Corina Giurgiu SeaCities, Cities Research Institute, Griffith University, Gold Coast, QLD, Australia Olv Klijn FABRICations, Amsterdam, The Netherlands Despina Linaraki SeaCities, Cities Research Institute, Griffith University, Gold Coast, Queensland, Australia Han Meyer Delft University of Technology, Delft, The Netherlands Thang Viet Nguyen SeaCities, Griffith University, Griffith, Australia Anne Loes Nillesen Defacto Urbanism, Rotterdam, The Netherlands Eugen Bogdan Petcu New York Institute of Technology, Old Westbury, NY, USA; School of Medicine, Menzies Health Institute of Queensland, Griffith University, Brisbane, QLD, Australia Alessandro Pezzoli Politecnico di Torino, Turin, Italy Eva Pfannes OOZE Architects & Urbanists, Rotterdam, The Netherlands Carlotta Quagliolo Politecnico di Torino, Turin, Italy Avery Robertson Independent Scholar, New York, USA Oz Sahin School of Engineering and Built Environment, Cities Research Institute, Griffith University, Brisbane, QLD, Australia; Griffith Climate Change Response Program, Brisbane, QLD, Australia Kelly Shannon KU Leuven, Leuven, Belgium Elnaz Torabi Griffith University, Gold Coast, Australia Julia Watson Graduate School of Design, Harvard University, Cambridge, USA; School of Architecture, Planning and Preservation, Columbia University, New York, USA Mona zum Felde Defacto Urbanism, Rotterdam, The Netherlands

Re-Building Coastal Cities: 20 Tactics to Take Advantage of Sea-Level Rise Joerg Baumeister

Abstract Current urban adaptation methods to Sea-level rise (SLR) derive mostly from technical- and economic-driven risk-management. It does not consider opportunities created by the complexity of cities which include social, productive, cultural, and ecological components. This chapter explores this research gap by reflecting known adaptation methods onto individual urban components. It focuses on the creation of opportunities resulting in a systematics that provides 20 urban adaptation tactics. These different tactics can be either applied individually or combined to strategies to achieve made-to-measure solutions. Compared to current adaptation methods, the tactics are expected to enable solutions which are more adaptable to specific challenges and locations. Thereby the tactics provide the additional potential to offset expenditures of SLR and to be more city, citizen, and environmentally friendly.

1 Sea-Level Rise (SLR) To better understand the effects and dimensions of global warming, we have to mention these effects briefly at the beginning: in the 1970s, the Club of Rome published with “Limits to Growth” forecasts on global warming and its impact (Meadows et al. 1972). Today, fifty years later, global warming is a fact, and no rational individual is questioning global warming anymore. The data situation and discussion have meanwhile refined, with probabilities of different warming scenarios being assessed (IPCC 2019) It becomes increasingly evident as to what extent global warming has so far produced unexpectedly high and diverse economic, ecological, social, and geopolitical risks. While “Limits to Growth” still largely addressed experts and interested laypersons, the problems of global warming are now perceived by the general public (World Economic Forum 2020). J. Baumeister (B) Cities Research Institute, Griffith University, Brisbane, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 J. Baumeister et al. (eds.), SeaCities, Cities Research Series, https://doi.org/10.1007/978-981-15-8748-1_1

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Today, it is common sense that greenhouse gases such as CO2 or methane, which are produced when fossil fuels are burned, are responsible for global warming. An increase in greenhouse gases in the atmosphere leads to higher temperatures which in turn causes sea-levels to rise. So there is a direct correlation between the proportion of greenhouse gases and SLR. A temperature-related melting or freezing, e.g. of the north and south polar ice, is, however, a slower process than an increase or decrease in temperature, which is why the greenhouse gas concentration and sea-level curve are shifted in time (see Fig. 1.1). The current greenhouse gas concentration of now over 400 ppm is the highest in millennia, and a corresponding record high of the sea-level will logically follow: in earlier phases of history with a similarly high greenhouse gas concentration, the

Fig. 1.1 (based on Hansen and Sato 2012): CO2 concentration, temperature anomaly, and SLR changes for the past 400,000 years

Re-Building Coastal Cities: 20 Tactics to Take Advantage …

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SLR was 15–25 metres higher (Jones 2020). The crucial question is therefore not WHETHER, but HOW FAST the ice will melt in the next decades. Current intensive research suggests that the more the melting behaviour and its collaterals are understood, the higher the predictions for SLR. New estimates still cannot “explicitly calculate changes in ice mass, partly because of the small scales necessary to resolve ice sheet processes properly, and partly because the relevant physical processes are poorly understood” (Pörtner et al. 2019). But the (always upward developing) predictions estimate a SLR of up to 1.40 m or more by 2100, and a simultaneous up to a 100-fold increase of “extreme sea-level events” (Pörtner et al. 2019).

2 Urban Flooding Global warming has several other effects in addition to rising sea-levels: the hydrological pressure on coasts changes the condition of groundwater, which can rise and become saline (Ketabchi et al. 2016). And the rising temperatures cause more dynamic movements of air and water, which leads to more extreme weather. Waterrelated consequences include an increase in the likelihood of heavy rain, which can lead to flooding of land and rivers (King et al. 2015). More water-related impacts of global warming and potential combinations of fatal impacts are highlighted in Fig. 1.2. SEA-LEVEL HAZARDS

COASTAL HAZARDS

DIRECT IMPACTS

Submergence of land Loss of land and land use Enhanced floding Loss of coastal + marine ecosystem services Local mean sea-level rise

Erosion of land + beaches

Local extreme sea-level

Salination of soils, groundwater and surface waters

Damage to people Damage to the built environment

Loss of + change in marine + costal ecosystems Damage to human activities Impeded drainage

Fig. 1.2 (based on Pörtner et al. 2019): Overview of the main cascading effects of SLR. “Mean SLR” describes thereby the sea-level halfway between high and low water, whereas “extreme sea-level” expresses the maximum level during a selected period like a year

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The example of New Orleans impressively demonstrates to what extent flooding events can substantially damage a city: New Orleans is located largely below sealevel and must, therefore, be protected by dykes. The weak point of this so-called polder situation is its susceptibility to flooding as a result of hurricanes, including the associated heavy rain and river flooding (Jonkman et al. 2013). Unfortunately, New Orleans had failed to maintain the levees so that they could not defy hurricanes. Before hurricane Betsy flooded the city in 1965, New Orleans had 625,000 inhabitants. Afterwards, considerable investments in flood protection subsequently led to a population increase to 500,000. In 2005, hurricane Katrina destroyed the city again. This time 80% of the city was flooded resulting in direct damage of US $ 40 billion and further investments of US $ 15 billion to improve flood protection. Despite the enormous efforts, the population has since halved to 300,000, and a large part of the economic power has moved away (Link 2010). Globally, the economic impact of flooding in correlation to SLR could average between 1 and 5% of GDP annually (see Fig. 1.3). An exclusive focus on the 400 million population living in the 136 endangered coastal cities with more than 1 million inhabitants will move the annual average costs of 1–5% GDP much higher (Hanson et al. 2010).

3 Re-Building Coastal Cities We have to Re-Build Coastal Cities: The upcoming rise in mean sea-level and extreme sea-level events will flood coastal cities increasingly (see 1.). Built and natural environment of coastal cities will be impacted dramatically including citizen’s health and the urban economy. This poses the question: How can coastal cities adapt best to SLR? One logical approach is to try to risk-manage SLR. Each measure is thereby often considered just as expenditure which tries to minimise damage of SLR (see 2.). The aim of this publication is to suggest a broadened perspective from risk management to the creation of urban opportunities (see 4.). It will consider thereby cities as specific complex structures consisting of buildings and spaces, economy, community, infrastructure, and natural environment (Baumeister and Ottmann 2015). This creates the opportunity to explore potential SLR adaptation methods for each of these urban elements. The method to explore potential opportunities will happen in the following way: the different urban elements will be described (5.) and current adaptation models analysed and, if required, optimised (6.). The combination of the urban elements with the adaptation methods in form of a matrix will allow the development of 20 tactics to take advantage of SLR (7.) which will be discussed at the end (8.).

Re-Building Coastal Cities: 20 Tactics to Take Advantage …

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Fig. 1.3 (based on Jevrejeva et al. 2018) showing predicted annual global flood costs (in % of GDP) without additional adaptation for three climate scenarios

4 Risks as Opportunities The effects of SLR after the last ice age are well documented (Galili et al. 2019). Related myths about coastal flooding developed thousands of years ago are still held today as part of indigenous cultures. An angry deity destroyed, for example, a port city with a flood in the Tamil epic Manimekhalai (Nunn 2014). Physical evidence of SLR thousands of years ago can be found in many coastal locations around the world, e.g. on the Yangtze River, where the Baoden people had to leave areas partially or built seawalls to protect themselves from flooding (Zeng et al. 2016). Another monument to the effects of SLR was recently discovered on the Israeli coast: During the underwater excavation of an approximately 7000-year-old settlement, a wall made of large stones with a length of more than 100 m was discovered, which stretched parallel to the coastline. The wall is now 90 m offshore about 3 m below the sea-level (Galili et al. 2019). Apparently, the residents had tried to save their

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city, which makes this sea wall to a memorial that can remind us of the limited nature of protective measures against SLR and its risk of physical and social disintegration. On the other hand, flooding can stimulate the reorganisation and regeneration of states and their economic resources, e.g. historically in Mesopotamia and Egypt. The relationship between human societies and floods created their advantages for agriculture, transportation, and trade that were decisive for the emergence of early civilisations (Soroush and Mordechai 2018). The history of other countries like the Netherlands (which is almost a third below sea-level) also shows how SLR can be viewed not only as a risk but also as an opportunity: as early as the ninth century, the collective reaction to flooding events played a community-building role in the Netherlands, which led to the success of elected boards as one of the first democratic institutions. The Dutch society had to be always open to new technologies for water management, construction, and transportation, and their joint development and financing models were the reasons for Holland’s rise to become a world power. Nowadays, in the period of increasing SLR, the Netherlands plays a central role in areas such as water management, land reclamation, and land defence (Van Kongingsfeld et al. 2008). Or, as announced in the New York Times, “The Dutch Have Solutions to Rising Seas. The World Is Watching. In the waterlogged Netherlands, climate change is considered neither as hypothetical nor as a drag on the economy. Instead, it’s an opportunity “entirely in the sense of “live with the water rather than struggle to defeat it” (Kimmelmann in New York Times 2017).

5 Urban Elements To achieve a far-reaching change from “defeat the water” to “living with the water”, the complete urban system has to be considered. Therefore, cities should not only be viewed from, e.g., purely economic but from a holistic perspective. The publication “Urban Ecolution” (Baumeister and Ottmann 2015) offers this holistic description of the city system which arranges the urban elements as a taxonomy. This reference system connects the physical, economic, social, and technical elements of a city. To achieve this, “Urban Ecolution” first analyses the history of urban configurations and tries to understand them as an urban metabolism. Then, ecology is presented as a system to remind us that we can do things differently to live with nature rather than the struggle to defeat it. Finally, it applies the principles of ecological systems to urban systems and describes the following system elements:

Buildings / Space

Production

Community

Infrastructure

Natural Environm.

• “Buildings and Space” are thereby residential, commercial, industrial, cultural, and special building typologies in combination with the surrounding urban space.

Re-Building Coastal Cities: 20 Tactics to Take Advantage …

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• “Production” includes industry, commerce, retail, aquaculture, agriculture, and forestry. • “Community” comprises culture, spirituality, education, research, recreation, governance, and politics. • “Infrastructure” describes the combination of transport, water, sewage, waste, power, and communication. • “Natural Environment” is the amalgamation of sun, air, biomass (plants, animals), minerals, and water.

6 Urban Adaptation Models for SLR After the description of the urban elements above, current adaptation models have to be analysed now. The aim is to combine afterwards the urban elements with the adaptation methods to develop a systematics of different opportunities for SLR. Therefore, the question is now how far there are already models (e.g. from coastal protection, ecology, and economics) that describe urban adaptation methods to SLR. The goal is either to adopt an existing model or, if necessary, to develop a new one. (a) A first adaptation model focuses on the adaptation method “Protect” to defend urban “assets” as suggested, for example, by C40: 94 cities and Ramboll Foundation thereby developed a framework, which measures the progress of urban climate-change adaptation. To combat storm surges and SLR, the framework includes the installation of flood gates to reduce storm surge flooding, a permanent coastline protection by building dykes and seawalls, a stabilisation of river banks with vegetation or concrete reinforcement as well as a relocation of assets which are at risk or an adaptation of assets by elevating or hardening them (C40 2019). (b) Other experts have proposed to organise a model which is based on the history of coastal engineering. For example, K. Hill suggests a model which builds on the physical form of walls and landforms (Hill 2015). Walls are thereby subdivided into static walls (seawalls, floodwalls) and dynamic walls (tide gates, movable surge barriers). The same distinction happens between landforms which are either static (levees, dykes, mounds, breakwaters) or dynamic (beaches, sand dunes and bars, marshes). These tools allow for the application of different adaptation methods called “Robust” (= to prevent negative consequences), “Resilient” (= able to recover), or “Adaptive” (not greatly affected by the event). (c) The World Bank suggests a model which considers three adaptation methods which react more divers on urban coastal areas: “Protect” reduces the likelihood of hazards, “Accommodate” reduces the impact of the hazard event, and “Retreat” reduces exposure by moving away from the source of the hazard. Technological and policy options are for

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• “Protect”: Dykes, levees, floodwalls, seawalls, bulkheads, flood gates and tidal barriers, detached breakwaters, periodic beach nourishment, wetland restoration, afforestation, wooden and stone walls. • “Accommodate”: Emergency planning, insurance, modification of buildings to cope with floods (strengthen and lift), improved drainage, strict regulation in hazard zones, modification of land use planning. • “Retreat”: Increase or establish retreat zones, relocate threatened buildings, phase out or ban development in areas susceptible to flooding, rolling easements, erosion control easements, upland buffers (World Bank 2017). (d) The United Nations’ Environment Programme created together with the World Meteorological Organisation in 1988 the IPCC (Intergovernmental Panel on Climate Change) which describes in Chapter 4 of its updated 2019 sea-level report one of the most comprehensive models. It follows thereby mostly the World Bank’s suggestions but adds subcategories and a new adaptation method: • Protection “reduces coastal risk and impacts by blocking the inland propagation and other effects of mean or extreme sea-levels” (Oppenheimer). Elements of the so-called hard protection are dykes, seawalls, breakwaters, barriers, and barrages to protect against flooding, erosion, and salt-water intrusion. Elements of the “sediment-based protection” are beach and shore nourishment and dunes. • Accommodation “includes diverse biophysical and institutional responses that mitigate coastal risk and impacts” (Oppenheimer et al. 2019). Accommodation measures include to lift buildings on stilts and podiums or to move water-sensitive functions of buildings onto higher floors or “floating houses and gardens” (Trang 2016). • Retreat “reduces coastal risk by moving exposed people, assets, and human activities out of the coastal hazard zone” (Oppenheimer et al. 2019). This includes “migration” which is voluntary, “displacement” as involuntary and unforeseen movement, and “relocation” which is a managed retreat typically implemented by governments. • Advance “creates new land by building seaward, reducing coastal risks for the hinterland and the newly elevated land” (Oppenheimer et al. 2019) comprising land reclamation by land filling, natural accretion by planting specific vegetation. Comparing the four SLR adaptation models, model (a) mainly considers minimising damage by preserving assets and is therefore excluded. The second model (b) suggests a variability between static and dynamic measures, but the small number of components allows only limited use in an urban context. In contrast to that, model (c) considers and sorts a much larger number of components. Model (d) is the most comprehensive and has a lot in common with proposal number (c). However, there is sometimes ambiguity of adaptation methods which swing between human, technical, and physical aspects. Consequently, in the following, a new model is developed to describe urban adaptation methods to SLR. It is based on model (d) and integrates components of (c) but also takes the following aspects into account:

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– The IPCC report describes “ecosystem-based protection” by plants as a separate adaptation method. Its main purpose is still to protect; therefore, we keep it as part of this response type. – Due to increasing attention to floating structures as urban development measures, we propose to include them in the adaptation method “Advance”. This results in the following four adaptation methods: Protect:

Either there is a hard respond as dykes, seawalls, breakwaters, barriers, and barrages, or it is sediment-based as beach and shore nourishment and dunes, or it is ecosystem-based including plants, wetland restoration, afforestation. Accommodate:

Accommodation measures include to lift buildings on stilts and podiums or to move water-sensitive functions of buildings onto podiums. Retreat:

Retreat zones, rolling easements, erosion control easements, upland buffers are increased or established, and threatened buildings relocated. Advance

Comprising land reclamation by landfilling as well as natural accretion by planting specific vegetation and floating structures are introduced.

7 20 Tactics The combination of both the defined adaptation methods and the described urban elements together create a systematics of opportunities responding to SLR. The

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individual elements will be called “tactics” which, in normal usage, are often equated with the term “strategy”. However, there are differences: While tactics reflect a single activity or technique, strategy rather refers to the “large, overarching plan in which parallel or successive tactics are coordinated” (Strategy in Encyclopaedia Britannica 2020). Therefore, the individual parts of the systematics are the tactics which will be created and described now. Afterwards, corresponding strategies which use different tactics as part of an overarching plan will be discussed. The tactics will describe opportunities for the different adaptation methods projected onto the various elements of the city, both as described above. This results in a matrix where adaptation methods can be applied in the vertical direction and the urban system elements in the horizontal. Buildings/Space

Production

Community

Infrastructure

Natural environment

Protect

1.

2.

3.

4.

5.

Accommodate

6.

7.

8.

9.

10.

Retreat

11.

12.

13.

14.

15.

Advance

16.

17.

18.

19.

20.

Each combination results in a tactic describing an opportunity for SLR. This is executed in rows for 1. – 5. (Protect), 6.– 10. (Accommodate), 11. – 15. (Retreat), and 16. – 20. (Advance). Tactics for “Protect” (1 .– 5.)

1. Buildings / Space

2. Production

3. Community

4. Infrastructure

5. Natural Environ.

The construction of dykes and other hard protection elements such as walls, barriers, and barrages align themselves against SLR. However, their height must be adapted to increasing SLR, whereby in the case of “Protect” the measures are becoming more and more complex. The base of dykes and the foundations of protective walls have physical limits to growth, which is the reason why it is more interesting in short to medium term. Exceptions are sediment—and eco-based nourishments, which ideally adapt to SLR automatically. Tactic 1 (Protect × Buildings): The logic of this opportunity consists in the functional development from a pure protective structure to the creation of additional building volumes for residential, commercial, industrial, cultural, and special buildings. This can reduce the construction costs of the purely protective structure, and at the same time, the city and urban spaces can expand.

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Tactic 2 (Protect × Production): In this case, the surface of the protective structure is used to enable additional functions resulting in commercial opportunities to produce wind or solar energy. Extensive as well as intensive agriculture is an option, also because the slightly salty note of the products (e.g. lamb meat or strawberries) is very popular for gourmets. In case of soft solutions, beaches and dunes contribute to the attractiveness for the tourism industry. Tactic 3 (Protect × Community): The sense of community strengthens with the common interest in the maintenance of the protective measures and the shared responsibility in extreme water events. The created landscape spaces such as dykes or dune landscapes also offer leisure areas to be enjoyed together. Tactic 4 (Protect × Infrastructure): The top of dykes as well as dune trails are attractive bike and footpaths. Additional infrastructure for extra energy supply (e.g. due to the wind or solar energy generated in tactic 2.) or for decentralised wastewater disposal can also be accommodated there. Tactic 5 (Protect × Ecosystems): Hard protective measures such as dykes or protective walls can be ecologically upgraded with plantings and thus contribute to the diversity of flora and fauna. The natural environment of sediment-based and ecosystem-based environments will undergo a constant process of change that can still be controlled by human interventions (such as planting indigenous trees). Tactics for “Accommodate” (6. – 10.)

6. Buildings / Space

7. Production

8. Community

9. Infrastructure

10. Natural Environ.

While “Protect” asserts itself horizontally against SLR, “accommodate” chooses the vertical. If possible, buildings can be raised, or water-sensitive functions can be moved upwards. Instead of these short-term limitations to flooding damages, the vertical “escape” from SLR can be achieved more sustainably in the longer term by building podiums either from piles or from sediments. If the podium is stable enough, it can be raised further in the future. While individual property owners invest in “Protect” in a common protective measure, the “Accommodate” measures take place directly on the individual properties, so that SLR can be reacted to both jointly as community and as private individual. Tactic 6 (Accommodate × Buildings): The volume required to create the podiums produces additional interior and exterior space. This allows the expansion of usable building space, and the protection of outdoor space against SLR. In a transition period in which the surroundings are only flooded during extreme events, the lower level and the outside space in front of it can be used almost without restrictions and, if necessary, protected by bulkheads.

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Tactic 7 (Accommodate × Production): Additional areas created in the podium can be used for industry, commerce, and retail. The podium level first produces added value as an additional access level. With increasing flooding, the relationship to water and the associated waterfront is strengthened, which can have a positive effect on the commercial value of uses (“Blue Economy”). Tactic 8 (Accommodate × Community): A slow move of public space from the natural surface to the podiums creates a restriction of freedom of movement on one side. On the other hand, a community feeling is strengthened, and public places are used more intensively which is comparable to the “sense of community” of island residents. The increasing proximity to water will also enhance “Blue Health” (describing the impact of waterbased environments on human health and wellbeing) and will create new leisure opportunities. Tactic 9 (Accommodate × Infrastructure): Infrastructure in flooded areas must adapt to SLR to ensure the functionality of buildings. The podiums can stay connected to the centralised infrastructure, which requires joint coordination and financing. However, SLR can also drive the opportunity to increasingly consider decentralised solutions (e.g. decentralised energy and water supplies or wastewater disposal) for the podiums. Tactic 10 (Accommodate × Ecosystems): The edges of podiums and pile foundations are amphibious transition zones between land and water, which, depending on the climate zone, can be ecologically upgraded with plants such as reeds or mangroves. Tactics for “Retreat” (11. – 15.):

11. Buildings / Space

12. Production

13. Community

14. Infrastructure

15. Natural Environ.

Retreat might appear as the least obvious opportunity to SLR since it abandons human-cultivated areas either temporary or permanent: Existing buildings and infrastructure become unusable, and therefore, values are destroyed and communities are exiled. However, a change of perspective can help to recognise positive aspects, because there are amphibious transition zones created which can be discovered and used by both humans and nature. Tactic 11 (Retreat × Buildings): While existing buildings and urban spaces are increasingly giving way to SLR, the edges of the flooding areas are becoming more and more attractive due to their increasing water frontage which can result in a denser development with urban spaces. At the same time, the floodplains can be equipped with observation or research stations and buildings can also be adapted to the amphibious way of life, which is described under Tactic 16.

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Tactic 12 (Retreat × Production): Depending on the respective climatic zone, aquaculture can grow products in flood areas such as rice or shrimp. Additionally, the cultivation of high-efficiency micro-algae can encourage a change of production towards bio-economy to substitute fossil carbon and to grow bioplastics, livestock food, and nutrients for food and health industry. Tactic 13 (Retreat × Communities): SLR displaces existing communities that have to be located elsewhere. At the same time, a change from an urban to more natural water landscape creates additional leisure opportunities, for example, for water sports, which makes these areas more attractive for communities. Tactic 14 (Retreat × Infrastructure): Amphibious transition zones can serve as flexible flooding areas for extreme events until these areas are flooded permanently. For example, what used usually as a parking lot can be flooded in an emergency. If surfaces are permanently flooded, they are ideal for boat traffic as a supplement to road traffic on the non-flooded surfaces. Tactic 15 (Retreat × Ecosystems): Increasingly flooded areas will be taken over by the natural environment wherever there is no countermeasure. Ecologically effective and indigenous vegetation should be explicitly supported (such as mangroves in tropical and subtropical climates with the associated ecosystems). Tactics for “Advance” (16. – 20.):

16. Buildings / Space

17. Production

18. Community

19. Infrastructure

20. Natural Environ.

“Protect” strengthens and protects the boundary between water and land, “Accommodate” moves it vertically, and “Retreat” draws the interface back horizontally. “Advance” also acts horizontally but in the opposite direction by moving the border from land to water. This land reclamation can take place either by expanding the mainland, by planting specific vegetation, or by placing floating structures in front of the land. Especially in the latter case, the elegance of the solution lies in its unique automatic adaptation to SLR, which is why we will concentrate on it. In all cases, legal boundaries shift from land to water so that the legal planning principles and new property relationships often have to be redefined. Tactic 16 (Advance × Buildings): Floating buildings not only extend urban uses and spaces but reduce the swell and thus protect the coast behind them. This construction method and the attractive water position can compensate for higher construction costs. Tactic 17 (Advance × Production): Proximity to water is desirable for commerce and retail. Its extension and the mobility of individual floating industrial plants also increases the flexibility of work processes and supply chains. Additionally, potential aquaculture farming enables

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efficient production of biomass either as a food base or to strengthen the secondary industrial sector (e.g. production of pharmaceutical products, energy and bioplastics). Tactic 18 (Advance × Community): Recreation areas and cultural institutions can expand from the shore to the water. What was preserved previously for boat owners can now be enjoyed by the entire population. The increasing density creates additional aquatic benefits to a larger community like facilities for “Blue Culture” (e.g. floating exhibitions) or “Blue Recreation” (e.g. floating parks). Tactic 19 (Advance × Infrastructure): Transport by boat, which is much more efficient than land transport is the most obvious opportunity. But in addition to that, there is the possibility of becoming more independent and at the same time more ecological from the existing infrastructure: wastewater can be processed, and freshwater and energy can be produced on site. Tactic 20 (Advance × Ecosystems): The massive positive impact of coastal protection by coastal and marine ecosystems is well understood. The creation of artificial reefs as well of floating islands will add value as wave-breakers and will create even more amphibious and aquatic ecological diversity.

Buildings / Space

Production

Community

Infrastructure

Natural Environm.

Tactic 1

Tactic 2

Tactic 3

Tactic 4

Tactic 5

Tactic 6

Tactic 7

Tactic 8

Tactic 9

Tactic 10

Tactic 11

Tactic 12

Tactic 13

Tactic 14

Tactic 15

Tactic 16

Tactic 17

Tactic 18

Tactic 19

Tactic 20

Protect

Accommodate

Retreat

Advance

In summary, examples of the different tactics exist (1. – 15.) or are yet to be fully explored (16. – 20.): Tactics 1. – 5. have been practised since the creation of polder landscapes (De Boer 2019) or even before, Tactics 6.–10. can be studied in storm surge areas such as in HafenCity Hamburg (Ge et al. 2013), Tactics 11. – 15. are currently used, e.g. in projects in New York (Howarth, 2014) and in the Delta Plan in the Netherlands (Van Hagen et al. 2015). And Tactics 16. – 20. can be seen for example in projects from SeaCities’ (SeaCities.org) or UN’s Floating Cities approach (UN-Habitat 2019).

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8 Discussion The tactics have been created systematically by projecting different adaptation methods onto different urban elements. Therefore, all are different, but there are also relevant similarities for further applications: PHASING: Tactics using the “Protect” and “Accommodate” adaptation method will only adapt to SLR to the point where the reinforcement of the security measures becomes more costly than the value of the areas to be protected. With rising sealevels, the production and maintenance of protective measures becomes more and more complex and consumes more and more space that was used previously for urban or ecological purposes. High costs of the protective measures in more impoverished cities will lead to the withdrawal of urban areas earlier (King et al. 2015). If areas cannot be protected or accommodated any more, they can follow tactics of the “Retreat” or “Advance” method. The latter can develop further offshore as proposed or it can also be applied on flooded areas inland to compensate the “Retreat”. OWNERSHIP: Tactics which follow the adaptation methods “Protect” and “Accommodate” try to preserve the current ownership structure and are therefore often the more preferred option by politicians and the community. The former ones want to protect the ownerships as a community, whereas the latter offers the possibility to develop the protection individually. Tactics following “Retreat” can only hope for compensation or an alternative property (like the following), whereas “Advance” tactics are opening up new development opportunities. GOVERNANCE: To maintain trust among the population and prepare for additional expenses, good governance must develop (and also communicate) a specific long-term plan for the radical measures that will be required to adapt to the SLR (King et al. 2015). COMBINATIONS: The coordination of above-mentioned components phasing, ownership, and governance can happen during the preparation and application of individual tactics. Due to the dimension of the SLR challenge and the complexity of cities, it can be more advisable to embed tactics in a strategy as “a large, overarching plan in which parallel or successive tactics are coordinated” (Strategy in Encyclopaedia Britannica 2020): STRATEGIES can be thereby developed out of the systematics in different directions, either as a combination of tactics – horizontally (= same adaptation methods) like Tactics 1. – 5. or 6. – 1 0. etc. – vertically (= same urban elements) like Tactics 11. + 6. + 11. + 16 or 2. + 7. + 12. + 17. etc. – selectively following a synergistic approach for an integrated and sequenced response to SLR (Oppenheimer et al. 2019). One example of a strategy of selectively combined tactics is the Deltaplan project in the Netherlands, which takes an SLR of 4 m in 2020 (Deltacommissie 2008) into account. It uses a combination of protection-tactics like Tactics 1.– 4. as well as

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retreat tactics like Tactics 11.– 14. and Tactics 5 .+ 10 . + 15. + 20. for the (re-) production of a diversity of ecological flooding areas (Van Koningsveld et al. 2008). The approach of a strategic combination of selected tactics goes hand in hand with the World Bank strategy, which declares, for example, tactics related to hard structures as not an economically viable solution. “In some cases, protective structures will still be necessary. However, the consensus is that the climate-change challenge should be used as an opportunity to adopt a long-term strategic approach” (World Bank 2017). According to a global survey, “failure of climate-change mitigation and adaptation is this year’s number one long-term risk by impact” (World Economic Forum 2020). The developed 20 tactics should be helpful to generate a variety of made-tomeasure strategies for a successful climate-change mitigation and adaptation. They can be applied in a next step to any coastal city under special consideration of its specific bioclimatic, socio-cultural, economic requirements. Regardless of whether the reader is an academic, government representative, entrepreneur or interested layperson, these 20 tactics resemble a tool set for everyone to develop and apply tactics and strategies as innovative opportunities for SLR which is one of the most urban challenges in the near future.

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Joerg Baumeister Prof. Dr.-Ing. Joerg Baumeister has been a practitioner, educator, researcher and consultant for Architecture and Urban Design for more than 20 years throughout Europe, Africa, the Arabian Peninsula, Asia, and Australia. As University educator with passion for "his" students, he tries to fuse research, higher education, and implementation in order to create feed-back loops to evolve the fields of Urban Design and Architecture. Joerg founded in 2019 the "SeaCities" research lab (SeaCities.org) at the Cities Research Institute, Griffith University to develop water-adapted cities and floating structures. He is consulting governmental institutions on the federal, state and regional level as well as NGOs and private industry leaders to apply his current research interests which comprises SeaCities, Ecological Cities, Affordable Housing in serial building technology, and Design Innovation through creative thinking. He is an award-winning Architect and Urban Designer and continues to be an enthusiastic speaker at international conferences. Joerg is DAAD Ambassador and Scientist For Future.

Design Strategies for Coastal Adaptation Urban Speculation in Palm Beach, Gold Coast—Australia Cecilia Bischeri

Abstract Sea-level rise has put under the spotlight the foreshore of our cities. The architecture of the foreshore has become subject to considerable investigation to understand how our cities can cope and thrive in a progressively mutable context. This slow-onset event and the physical transformation provoked present a fascinating scenario and an incredible opportunity to challenge the way we conceive, organise and design coastal cities. At the base of this opportunity lies a paradigmatic shift on the belief that the land we occupy controls water. As da Cunha (2019) states, “the act of separation [between land and water] is a land-centric idea conceived to contain and control wetness.” From this perspective, any change to this “state of control” is deemed as a disruption or risk which promotes uncertainties in our social systems and infrastructures. This study investigates design strategies for urban adaptation of coastal developments. Considering the architectural perspective, the precedents and approaches presented combine landform infrastructures with interventions at the architectural scale. The preferred context of the application is Palm Beach in the City of Gold Coast, Queensland (Australia). The primary goal of this study is to present a speculative scenario for a neighbourhood within Palm Beach. Considered as a speculative project, the proposal aims to spur a constructive conversation on innovative design solutions able to influence the local architectural practice. The design proposal tests two different, yet related options. The first attempt is based on the Fingers of High Ground project by Mathur et al. (2014). The project’s key aspect is the manipulation of contours with the intent to mitigate and contain water while providing a territorial infrastructure. The second iteration, labelled Hybridised Canal Estate, couples the moulding of contours with the provision of sought-after real-estate waterfront properties. This iteration pivots around two main characters of the target community and context: the leisure driven tourism and real-estate market. Ultimately, this study aspires to promote a broader conversation on how to envision an innovative architecture of the foreshore able to transform the threat of sea-level rise into an opportunity to rethink our cities. C. Bischeri (B) Architecture and Design, School of Engineering and Built Environment, Gold Coast Campus, Griffith University, Brisbane, QLD 4222, Australia e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 J. Baumeister et al. (eds.), SeaCities, Cities Research Series, https://doi.org/10.1007/978-981-15-8748-1_2

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1 Introduction: Study Drivers Sea-level rise falls within the slow onset events provoked by climate change. Sealevel rise is here investigated in its relationship with the architecture of the foreshore and the development of design strategies required for coastal cities to adapt in this ever-changing context. The global average sea-level rose at a rate of 3.3 mm per year from 1993 to 2009 (Cazenave and Llovel 2010; Nicholls and Cazenave 2010). This figure is destined to grow and, in fact, the dramatic change and accelerated melting of the polar ice sheet mass support the depiction of a future where sea-level will reach, in comparison to the present-day situation, an estimated +0.8 m by 2100 (IPCC 2012). This last value is the most cited in the scientific arena, and the projection is based on intermediate carbon emissions and relatively stable Antarctic ice sheets (Kopp et al. 2014). In October 2019, Scott Kulp and Benjamin Strauss published a study on a more accurate way to measure land elevation from satellite images—called CoastalDEM.1 This new method has cast light on the actual number of people who live on lowlying coastal areas and, therefore, are going to be affected by sea-level rise. Kulp and Strauss (2019) state that “190 million people […] currently occupy global land below projected high tide lines for 2100 under low carbon emissions, up from 110 million today”. “Under high emissions, CoastalDEM indicates up to 630 million people live on land below projected annual flood levels for 2100.” Considering the national and global calibre of many of the cities involved in the projections, such as Shanghai, Bangkok and Amsterdam, it is reasonable to argue that relocation will not be an option and sophisticated strategies need to be implemented to cope with this mutable context. Urban planner, Lynch (1990, p109) stated, “A city is hard to kill, in part because of its strategic geographic location, its concentrated, persisting stock of physical capital, and even more because of the memories, motives, and skills of its inhabitants.” The question that awaits to be answered is, how are our cities and community going to adapt? This study emerged from the desire of testing design solutions for coastal resilience at the neighbourhood scale in the City of Gold Coast, Queensland— Australia. Three drivers need to be unfolded to clarify the research aims. The first driver is constituted by understanding the role of the architectural discipline in the provision of resilient solutions for cities and communities against, in this particular case, sea-level rise. The role of architecture in supporting resilient communities has almost solely been circumscribed to restorative actions; in other words, architects have been consulted and deployed with the main scope of providing solution during the reconstruction phase in the aftermath of a disaster. The shift required aims to invest the discipline with a more proactive role in the enhancement of resilience for the targeted communities. In addition, it is here argued that the distinctive role of architecture, in comparison to sister disciplines such as the engineering disciplines, lies in picturing a vision for the city. In fact, while engineering focuses on technical solutions and their implementation are primarily delivered through an additional 1 See:

https://go.climatecentral.org/coastaldem/.

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apparatus to the city forms, architecture enables the integration of those technical strategies, with programs and places for the community to live in and experience. Within this scenario, architectural innovation can proliferate. Secondly, this study relies upon previous work dedicated to understanding how to enhance community resilience and how architecture can facilitate the process. The main lesson learned is the value of architecture in supporting the construction, maintenance and intensification of social networks. What differs the current study from the previous is the change in scale. This investigation, in fact, moves from the architectural artefact to the neighbourhood scale. Before going any further, the role of social networks within this study has to be outlined. Notwithstanding the vast and multidisciplinary literature acknowledging the part played by social networks (Cutter et al. 2008, Sherrieb et al. 2010, Vale and Campanella 2005), also defined as social capital, in building community resilience and driving recovery, government guidelines and investments have often overlooked this factor. This study, on the contrary, acknowledges the role of social networks and foreground it as one of the design principles of the presented proposal. Focusing on tangible costs and aiming to minimise expenditure while providing safety to communities, the government response to risk has focused on investing resources in hard infrastructures notwithstanding the evidence that social infrastructures are at the core of resilient communities (Aldrich and Meyer 2015). A fundamental aspect of a healthy, functioning and resilient community is constituted by the three types of networks that social capital embodies. Those are bonding, bridging and linking. The primary reference for a detailed description of the three types of social capital remains the work of Daniel Aldrich (2012). However, in nuce, bonding is the network an individual established with their family members, friends and neighbours. Bridging involves the connection with external networks, different for demographic, religion or ethnicity. Aldrich (2012) labels bonding and bridging as horizontal, connecting groups of the same status.2 Linking, instead, is a vertical connection where groups interact with formal or institutional power or authorities. Mileti and Gailus (2005, p 498) have recognised the disenfranchisement “from power and influence” as an important factor in affecting negatively the community’s capacity to recover from natural disasters. The three levels are equally essential. In conclusion, social capital is more than an ideological stand and informs how and what can be designed to enhance community resilience by providing a framework of the community’s needs. Architecture, therefore, cannot limit its relevant space of manoeuvre to the single building and its technical aspects; on the contrary, the discipline needs to engage with the city and focus on the systems of networks which can fundamentally enhance community resilience. Foregrounding social relationship has to be the driver for an architecture of resilience, and understanding the character and needs of the target community is of paramount importance to be successful in this process. Needless to say, the promoted position does not intend to discredit the role 2 See:

Woolcock (2002). Social Capital in Theory and Practice: Reducing Poverty by building Partnership between states, Markets and Civil Society. In Social Capital and Poverty reduction: Which Role for Civil Society Organizations and the State? 20-44. France: UNESCO.

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of hard infrastructures and disaster-ready artefacts. Yet, the emphasis posed on social relationships aspires to encourage a shift, where the built environment is conceived in relation to its larger context. Infrastructures with doubling-up programs able to address the need to adapt while providing assets to the community should be the norm. Lastly, the financial return cannot be emphasised enough. Looking into the Australian panorama, in fact, the damages on community connectedness together with health and wellbeing impacts are considered intangible costs provoked by a natural disaster (Australian Business Roundtable for Disaster Resilience and Safer Communities 2016). While generally, the economic costs for natural disasters have been estimated around tangible costs (direct and indirect), recent literature has demonstrated that intangible costs may be underestimated by at least 50% (Australian Business Roundtable for Disaster Resilience and Safer Communities 2016). Therefore, a vision for the architecture of the foreshore constitutes an incredible opportunity to provide alternative visions for our cities combining urban forms with resilience. In addition, the architecture discipline could take a leading role in supplying solutions which engage with tangible (built environment) and intangible (wellbeing and community connectedness) domains. The last driver is constituted by a design intuition originated by observing how past civilisations adapted to the phenomenon of sea-level rise. Among the results presented by Kulp and Strauss in a divulgatory article published by The New York Times, the city of Basra is showcased to demonstrate the impact of sea-level rise and the extent of inundation to be expected (Lu and Flavelle 2019). Apparent is the need to equip the city and its territory with design solutions enabling communities to adapt to the profound reshaping of their context. The case of Basra becomes instrumental to this discussion. Basra, today located in southern Iraq, was part of the region known as Mesopotamia. Jennifer Pournelle, archaeologist specialised in the genesis of urban settlements, is here cited for her studies on the ancient Mesopotamian landscape during the dramatic sea-level rise occurred in 4000BCE. What is relevant to the present discussion is the similarity between the reconstruction of the Gulf’s inundation and the projections depicted by the future sea-level rise (Fig. 2.1). Hence, it appears pertinent to report how the then threaten population coped and adapted. To respond to the then rising water and vast inundation, the nomadic populations occupied finger-shaped ridges, called turtlebacks, which were elevated from the flood overlay, and surrounded by marshes and wetlands. Those locations of highground did not just offer a dry spot but supported by the richness of flora and fauna of the marshes became the sites for the proto-urban developments which morphed the basis for the rise of urban centres like Uruk, where writing was first invented (Pournelle 2003, 2007). This digression aims to spur a constructive conversation on how the threaten cities should undertake the journey for adaptation; and reflect on the opportunities offered by a high-impact phenomenon to revise and ameliorate current urban practices; acknowledging the need for a transdisciplinary approach able to surpass palliative and punctual solutions; and finally the urgency of innovative urban forms to enable adaptation.

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Fig. 2.1 Comparison of inundations in Basra (Southern Iraq) in 4000BCE and 2050CE a Basra in 4000BCE. Visualisation based on Pournelle’s reconstruction and visualisation. Source Lawler (2011 p.141) b Basra in 2050CE. Visualisation based on Kulp and Strauss’ projection and visualisation. Source https://coastal.climatecentral.org/map/7/49.4576/30.7947/?theme=sea_level_ rise&map_type=coastal_dem_comparison&contiguous=true&elevation_model=best_available& forecast_year=2050&pathway=rcp45&percentile=p50&return_level=return_level_1&slr_model= kopp_2014

2 Design Strategies In two previous studies (Dupre and Bischeri 2019, Bischeri 2015) focused on the architecture of resilience, a set of transferable guidelines on design criteria to support the planning and realisations of resilient communities have been produced. The guidelines have been drawn from comparative studies and good-practice examples of architectural precedents that pose the intensification of social networks as their driving concept. Four criteria, namely, (1) location, (2) function, (3) compositional strategies and formal expression, and (4) community involvement, have been identified as aspects which have a clear impact on providing an architecture of resilience. In addition, a definition of contextual factors related to the moulding of community identity has been taken into consideration. This framework lies on the background of the present study and has guided the selection and review of relevant factors to form an initial understanding of the targeted community identity. Seeking to provide a design response to the neighbourhood level, rather than the single building, further investigations are required. Four aspects have been central in shaping the proposal: (a) adopting a system to support the choice and application of coastal adaptation strategies; (b) investigating the neighbourhood scale which provides the opportunity to engage with the urban fabric while experimenting with the urban forms at a controllable scale; (c) investigating the identity of the targeted community via its context, physical and social characters; (d) identify good-practice examples which address similar issues and provide solutions through architectural strategies. A brief summary is here introduced to outline the main findings of this investigative phase.

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a. Design strategies for coastal adaptation: embracing a fluid ordering system The recent literature on design approaches to cope with sea-level rise pivots around a clear message: adaptation can be achieved when coastal solutions work with nature rather than against it. Most authors have organised the available coastal engineering practices into categories with the intention of providing an interpretative key to the understanding of options and type of approaches for designers, governments or other stakeholders. This study has no ambition of proposing a new system of categorisation, but rather to reflect on two specific aspects which accompany conventional engineering strategies and support their translation into architectural artefacts for the foreshore. The two aspects are introduced with the aim of advancing a more holistic approach for the urban foreshore via the surpass of palliative solutions and the push forth of revised urban forms to support adaptation. This study relies on the system of classification presented in the work of Kristina Hill, to promote a shared understanding of the existing infrastructures for coastal resilience. Particular interest is laid on her simple, yet sophisticated, approach which bridges the gap between listing the options available within the infrastructures for coastal resilience and the provision of valuable instruments to guide the selection and application of those very options (Hill 2015). In fact, rather than pigeonholing strategies according to the most broadly adopted two main criteria—1. Are those infrastructures natural and nature-based or conventional?3 2. What is the level of control those infrastructures apply to water?—Hill proposes a more fluid way to proceed. Hill’s method puts forth the use of typologies which are defined following Doty and Glick (1994, p 230) definition of “conceptually derived interrelated sets of ideal types.” The adoption of typologies is deemed as an important tool during the decisionmaking process (Hill 2015). The infrastructures are grouped under four ideal types. Those are walls, static (i.e. seawalls and floodwalls) or dynamic (i.e. tide gates and movable surge barriers); and landforms, static (i.e. mounds, dikes and canals) or dynamic (i.e. beaches, dunes and wetlands). The available options have clear pros and cons which need to be considered in the design process. Any coastal infrastructure, in fact, has an impact on natural systems and has to be accounted for during the feasibility study. For a more thorough analysis, the work of Hill is recommended. However, a brief overview is here offered via the Table 2.1. Hill’s classification does not provide a definitive matrix of solutions but rather a field, open to testing. And, Hill (2015, p 472) states, “the intent of the typology 3 See:

Bridges et al. (2015) Use of natural and nature-based features for coastal resilience. Washington, DC: US Army Corps of Engineers. http://www.nad.usace.army.mil/Portals/40/docs/ NACCS/NNBF%20FINAL.pdf. The adoption of wetlands, marshes, beaches, dunes, corals and other coastal ecosystem have been proved to be not only effective in supporting coastal resilience but also beneficial to maintain balanced and healthy ecosystems. The US Army Corps of Engineers has labelled those components natural and, nature-based features, which can be considered as an upgrade of conventional engineering strategies, they might occur naturally in the observed landscape or are engineered and built to mimic natural conditions.

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Table 2.1 Comparing advantages and disadvantages in Hill’s typology approach Walls

Advantages

Disadvantages

-well suited for punctual interventions

-incapability to adapt to new scenarios -impossibility to provide doubling up functions -potential of mechanical or power failure (limited to dynamic walls)

Landforms -well suited for addressing city-wide or -need for constant maintenance and regional issues monitoring -can be built in phases -can be adjusted to new circumstances -opportunity of doubling-up functions (this expands the benefits that landform interventions provide to the community)

is to represent the range of choices that could be applied, but the selection of the specific types of infrastructure that should be applied requires a review of the specific context.” Hill’s approach removes the safe feeling of having a list of possibilities and engages with a more inquisitive approach where the specificity of the context becomes of paramount importance. The context put forth in Hill’s argument refers primarily to the ecological dimension and built environment (use, density and urban morphology) with a broader consideration to the adjacent territory which is likely to impact and be impacted by the design and implementation of coastal infrastructures. The present study adopts solutions based on the landform type. Notably, Hill’s cited study targets the city or region; while, the current research aims to produce speculative solutions for the neighbourhood scale. In this scenario, therefore, the context has to assimilate and reflect on the fine grain of the socio-economic conditions and level of social capital present in the area. b. The Neighbourhood scale Dealing with the complexity of an entire city is beyond the capability of the present study; however, testing design solutions at the neighbourhood level offers the opportunity to engage with the intricacy of the urban fabric and its formal and functional requirements while maintaining a manageable size. This scale, in fact, encompasses the building dimension without alienating the city system and its infrastructures. In addition, it provides the prospect to reflect on the neighbourhood’s components and their adoption for facilitating the introduction of structures of coastal resilience at the urban scale. This approach draws inspiration from a speculative matrix proposed by Paul Lewis in the recent publication (Nordenson et al. 2018) titled “Structures of Coastal Resilience.” Yet, the presented proposal, instead of limiting the outcome to the hybridisation of a single element (i.e. a road, with a resilient infrastructure, such as a bulkhead), encompasses the entire urban block. The reason behind this approach lies on the opportunity to surpass punctual interventions to promote a more holistic approach where all the main elements considered are involved. A series of diagrams support the visualisation of the process which has been undertaken.

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The pictorial apparatus provides a storyboard for the advanced proposals. The first step consists of identifying the most basic components which form a neighbourhood notwithstanding its primary driver, i.e. residential, mixed-use, privately owned, etc. The three elements identified are green, buildings and circulation. It is here argued that we can achieve any type of neighbourhood just by varying the connotation of each of those elements. In other words, we can consider the component green as an element able to vary between private, the backyard garden of a house, for instance, to recreational, a park equipped with facilities. Similarly, buildings vary between private and public while circulation between vehicular and non-vehicular. Those parameters can be adjusted with the intent of reflecting the character of a current or envisioned neighbourhood. Having set the connotations for the three components, the following step consists of implementing strategies of coastal resilience in the urban form of the neighbourhood with the intent of embedding, rather than overlaying, resilience and adaptation. To maintain the speculation valuable, two premises need to be acknowledged. Firstly, it is assumed that the examined neighbourhood is equipped with a safe connection to the primary arterial system. Secondly, the speculative design work has focused on a neighbourhood where a water frontage is present (Fig. 2.2). c. Architecture for the bigger picture: Two Exemplars With the intent of presenting a speculative project for a neighbourhood in Palm Beach, the proposal has required some groundwork and the selection of two good-practice examples. The first project is the Big “U” by the BIG Team.4 The Big “U” aims to improve flooding resilience for the southern side of the island of Manhattan, New York. Yet, it also provides an opportunity to demonstrate the role of social capital and its impact on how and what it can be designed to enhance community resilience. The low-lying terrain of the area contains, on the one hand, Wall Street and on the other 35,000 affordable housing units. The project was initiated in the aftermath of Hurricane Sandy (2012). The project constitutes a protective system which stretches for approximately sixteen kms. Labelled by the designer team as a social infrastructure, the proposal interacts with a very dense, highly vibrant and socio-economically diverse community. The Big “U” is here presented as an exemplar in highlighting the existent inequality among the pockets of communities living in the area and investigating design solutions to mitigate the discrepancy. The mapping of ethnicities, annual income, public transport system, outline a strident fracture between the wealthy, white and well served West Side and the economically disadvantaged, not white and not well-served Lower East Side (LES). The architectural response focuses primarily on understanding how the Big “U” could facilitate change through the provision of resilient infrastructures and amenities able to enrich, connect and address with specificity the LES community’s needs while providing access to the river. The second project is titled Fingers of High Ground (FHG) by Anuradha Mathur and Dilip da Cunha. The project seems to emulate the aforementioned Mesopotamian 4 See:

http://www.rebuildbydesign.org/our-work/all-proposals/winning-projects/big-u https://big. dk/#projects-hud.

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Fig. 2.2 Structures of coastal resilience at the neighbourhood scale a Neighbourhood components b Typical residential neighbourhood layout c Coastal resilience strategies Source Hill (2015) d, e, f Embedding coastal resilience strategies in the neighbourhood urban forms: Dike crossed with neighbourhood components

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turtlebacks via a highly constructed and anthropised proposition. The project is part of a larger venture supported by the Rockefeller Foundation which was dedicated to studying and proposing resilient infrastructure for the North Atlantic coast of the USA after the devastating landfall of Hurricane Sandy and the consequent flooding events. Mathur and da Cunha focused on Norfolk in Virginia. The potent message the projects puts forth for the site is “Norfolk does not call for barriers and protection; it calls for design interventions on the basis of a new visualisation of the coast as a place where land meets sea, not across a line, but in a field of points.” And, “land does not meet sea across a ‘front’, but rather through a number of discrete fingers of high grounds. Each finger is a unique gradient or a unique gathering of gradients between land and sea, working to structure a coast that is more fractured, cumulative and diverse than it is continuous, linear and absolute” (Mathur et al. 2014, p147). The FHG project is here presented for two reasons. Firstly, the proposal deems to provide fertile material for the discussion and formalisation of a hybrid canal estate able to combine innovative, resilient urban forms with the extension of water frontage for real estate development and facilities. This scope is informed by the investigated context and further explored in the following section, d. The context: Palm Beach. Yet, differently from the canal estate, FHG are a territorial infrastructure morphed around an attentive observation of the existing geology, morphology and topography of the region subject of the study. FHG have a tectonic anchorage to the land which lies behind the foreshore and “can serve as islands of refuge and protective barriers in times of storm and surge” (Mathur et al. 2014, p149). In fact, they do not just provide a safe higher territory to occupy; FHG protect and limit the extent of inundation while reshaping the coast. The fundamental belief which informs the work of Amathur and da Cunha (2019) pivots around the fact that “land and water are products of an intentional act of separation carried out with the help of a uniquely endowed line drawn in a chosen moment of time. Water, however, seems to always be lesser in this difference, confined as it is by the same line to a place in waterbodies that are made to serve land—draining it, irrigating it, providing it with a waterfront for real estate, even making it with depositions of silt, but primarily keeping it dry for settlement.” The slant proposed by the two landscape architects offers a shift of perspective, enabling for a reimagined foreshore where land, water and infrastructures find a new balanced coexistence. d. The context: Palm Beach The City of Gold Coast, in Queensland—Australia, is located within a greater urbanised region, known as South-east Queensland. Characterised by subtropical climate and a low-lying, flood-prone coast, the region is nestled between the Great Escarpment, on the west, and the Pacific Ocean on the east side.5 The slow-moving and bend-rich water streams are the ideal habitat for wetlands and marshes. Within 5 See:

Oilier C. D. (1982) The Great Escarpment of eastern Australia: Tectonic and geomorphic significance, Journal of the Geological Society of Australia, 29(1-2): 13-23, https://doi.org/10. 1080/00167618208729190.

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this broader context, the City is punctuated by canal estates which are broadly recognised as part of the local character. Their ubiquitous presence is the testimonial of the transformation process the City has experienced. Starting from the beginning of the last century, the ocean, its sandy beaches and tourism turned a series of frontier townships in the Gold Coast phenomenon. The City is tightly connected with water, not just for its physical presence but for its exploitation as one of the elements of a larger apparatus concentrated around leisure. In 1997, architecture and design theorist Goad (1997, p36) in preparing an urban heritage and character study for the City Council wrote: “In Australia, the Gold Coast represents a peculiar and unique urbanism. Shunned by the tastemakers, it is nevertheless a vital part of our hybrid culture with its artistic, social and economic allegiances drawn from all over the globe.” And, “It is almost certain, that the current growth and continuing vibrancy of a culture sustained almost solely by leisure will presage a new cultural and urban condition for the twenty-first century.” The appearance of the canal estates in Gold Coast marked the turn of the city from an agricultural and sparsely inhabited region to a tourist destination. The first canal estate subdivision was approved in Gold Coast in 1956. This new form of development seemed to match the expectation of the developers, who aspired to extend the coastline to provide direct water access to the holiday-house owners while reclaiming cheap land from swamps and lowland forests. In the beginning, the process was driven by speculation and lacked regulation. However, the opportunity of exponentially extend the waterfront available for real estate demand favoured their adoption. Notwithstanding the environmental toll on the native wetlands and the increase of property exposure to flooding risks, the canal estates have been a significant instrument in the modern urban development for the City of Gold Coast.6 The suburb of Palm Beach, in Gold Coast, has been selected as a site for speculative propositions for four reasons. Firstly, due to its low-lying terrain, Palm Beach is exposed to seasonal flooding having the Tellebudgera Creek and Currumbin Creek to define, respectively, its northern and southern boundaries. Secondly, due to the proximity with the estuaries of the two aforementioned creeks and presence of canals, sea-level rise projections forecast that large part of the suburb will be inundated during king tide events. Those projections consider future changes to climate, incorporating the projected increase in sea-level of 0.8 metres by 2100. Additionally, a projected 10% storm tide intensity and 10% rainfall intensity increase have been factored in the flood overlay map. Lastly, Palm Beach is characterised by a low socio-economic demographic profile, which is generally associated with lesser community resilience. The Index of Relative Socio-economic Disadvantage (IRSD), one of the four indexes which form the Socio-Economic Indexes for Areas (SEIFA), is adopted to underpin the previous statement (Australian Bureau of Statistics 2018). The Index considers 6 See: Bosman et al. (2016) Off the Plan : The Urbanisation of the Gold Coast. Clayton, Vic: CSIRO

PUBLISHING. https://search-ebscohost-com.libraryproxy.griffith.edu.au/login.aspx?direct = true&db = nlebk&AN = 1164333&site = ehost-live&scope = site In particular the following two chapters: All that glitters: an environmental history ‘sketch’ of Gold Coast City by Bosman and Houston and City with/out a Plan by Dedekorkut-Howes and Mayere. Leach (2018) Gold Coast: City and Architecture. London: Lund Humphries.

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criteria such as income, educational attainment, unemployment and jobs in relatively unskilled occupations.7 Ultimately, the site analysis has highlighted the scarce and scattered presence of socio-cultural facilities in the area. This last factor showcases the lack of structures supporting the flourishing of social capital. Those considerations have played a fundamental role in driving the choice for the project site (Fig. 2.3).

3 Project Exegesis The previous analyses have provided the design strategies and criteria to inform the development of the proposal for Palm Beach. Considering all the listed factors—from the lack of a system of social and cultural facilities; the topography and character of the site; exposure to flooding and the essential role played by leisure within the framework of the city—a landform strategy is preferred for the benefits that can provide to the community. Therefore, thinking on the opportunities to yield on the integration of strategies of coastal resilience with the three identified neighbourhood’s components and local urban form, the proposition for a static landform (dyke) is put forth. The ambition lies in presenting a dyke hybridised with a canal estate. This aims to embed the desirable aspects of the canal estate developments while bypassing the detrimental effects of inappropriate development and the re-establishment of marshes. Additionally, the Hybridised Canal Estate (HCE) model accommodates the predicted population growth, which sees the Gold Coast as the most populous region in Queensland (Queensland Statistician’s Office Queensland Government projections 2018); provides a more democratised access to the water; and, double-ups and maximises the financial return for the investment in resilience strategies, via the enhancement of quality and quantity of community assets. In this context, community assets refer to those associated with place, namely built and natural assets (Flora et al. 2015). The attention to these specific components is linked to the importance of social capital in building community resilience. The proposal of an HCE might provide a plausible option in the design of a resilient future where the built environment has a proactive, rather than defensive, role in equipping communities with resilience strategies. The manipulation of a static landform, a dyke, with the three components of the neighbourhood has progressed via a process of formal analogy in the testing of the concept of Fingers of High Ground introduced by Mathur and da Cunha for the selected site. The FHG are identified with dykes which lay perpendicular to the shoreline and extend inland. The proposal has incorporated and valued aspects of 7 The

SEIFA Index is developed by the Australian Bureau of Statistics and ranks areas in Australia according to relative socio-economic advantage and disadvantage. The indexes are based on information from the five-yearly Census. The last data available refer to the 2016 census. For this study, the data have been gathered focusing on SA1 (Statistical Areas Level 1). The definition of SA1 can be found here: https://www.abs.gov.au/ausstats/[email protected]/Lookup/by%20Subject/1270.0.55.001 ~ July%202016 ~ Main%20Features ~ Statistical%20Area%20Level%201%20(SA1) ~ 10013.

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Fig. 2.3 Palm Beach. Framing the Context a The updated mapping considers future changes to climate, incorporating the projected increase in sea level of 0.8 metres above present-day levels by 2100 established by the State Government in 2015. The updated mapping also includes the State Governments projected 10 per cent storm tide intensity and 10 per cent rainfall intensity, based on advice from industry representatives. Sourcehttps://www.goldcoast.qld.gov.au/council/flood-hei ghts-maps-2222.html Source b Index of Relative Socio-economic Disadvantage (IRSD). Source https://www.abs.gov. au/ausstats/[email protected]/Lookup/by%20Subject/2033.0.55.001~2016~Main%20Features~SOCIOECONOMIC%20INDEXES%20FOR%20AREAS%20(SEIFA)%202016~1 c Existing social and cultural facilities: 1. Gold Coast Recreation Centre, 2. Tallebudgera Leisure Centre, 3. Beach, 4. Palm Beach Surf Club, 5. Palm Beach Neighbourhood Centre, 6. Thrower House Youth & Community Hub, 7. Palm Beach Scout Den, 8. Palm Beach & Currumbin Sports Club d The selected neighbourhood for the testing design propositions

the physical (i.e. topography, flooding points of access) and societal (i.e. cultural and social facilities) context, guiding the selection of the anchorage points for the insertion of this territorial infrastructure. The Gold Coast Highway runs parallel to the ocean and constitutes the highest point in the area. This artery provides one of the anchorage points for the FHG which branches towards the existing canals. The positioning of the secondary branches provides connections with the surrounding neighbourhoods and their primary social infrastructure, a tourist park, school and sports facilities. Concurrently, the FHG limit the impacts of flooding events. In fact,

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the branches are positioned strategically with the scope of isolating the two lowest elevation points of the area and circumscribing the extent of flooding water accessing the neighbourhood and inundating the residential developments. The architectural solution for the FHG is presented via architectural precedents and diagrammatic sections which demonstrate the intent of coupling architectural artefacts with the consistent presence of green space equipped with recreational activities and designed to adapt to the ever-changing water levels (Fig. 2.4). For the second test, the lessons learned from the application of the FHG are applied to the canal estate. The intent is to provide a resilient urban form paired with the favourable aspect of the canal estate, an extension of water access. Furthermore, the provision of additional community facilities, which work in synergy with the existing one, enriches community assets while facilitating the strengthening of social networks. To achieve such an ambitious outcome, the neighbourhood is profoundly reshaped in its urban form and topographic conformation. Networks are morphed through new and existing facilities. The system underpinning the network of facilities becomes the spine of the new residential development and arms the proposition with stepped parks and infrastructure able to adapt to flooding events. The master plan of the HCE presents a balanced diversity of functions—commercial-, medium- and low-density residential—and community-driven infrastructures. Their positioning takes advantage of calculated locations offered by the Gold Coast Highway (i.e. high traffic and visibility) for the commercial business, and prime water front site for the low-density development enhanced by intense greenery, amenities and a more democratised access to the water (Fig. 2.5).

4 Conclusion This study has investigated design strategies for urban adaptation of coastal developments in Palm Beach. The precedents and approaches presented combine landform infrastructures with interventions at the architectural scale. The study has presented two speculative scenarios for a neighbourhood. The proposals have moved through stages and testing which were recorded in the presented diagrams. Considered as speculative projects, the proposal aims to spur a constructive conversation on innovative design solutions able to influence the local architectural practice.

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Fig. 2.4 Testing fingers of high ground in Palm beach (with Carina Soleckhan) a The proposal responds to the context. Existing activity anchorage points: 1. Tourist park, 2. Education facility, 3. Sport/recreation facility b Schematic master plan and design propositions via architectural examples. 1. Adoption of Minghu Wetland Park, China by Turenscape (2012) to promote adaptation in the tourist park; 2. Student housing, Italy by Aldo Rossi (1974), to promote housing solutions to occupy the slope and maximise the use of floodable green areas; 3. Swimming pools, Switzerland by Aurelio Galfetti (1967), inhabited urban connector to support and enrich the network of community facilities while providing adaptative solutions. c, d Housing solution on fingers of high ground

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Fig. 2.5 Testing hybridised canal estate in palm beach (with Tahlia Wright) a Stages of implementation: 1. Present day, 2. Stage 1: 10 years, 3. Stage 2: 30 years, 4. Stage 3: 40 years, 5. Future extensions. b 1. Existing site section, 2. Proposed site section. c Network of existing and proposed community facilities d Program zones: 1. Low-density residential, 2. low-density residential, 3. community, 4. medium-density residential, 5. commercial. e master plan, f, g community facilities

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References Aldrich DP (2012) In: Building resilience: social capital in post-disaster recovery, University of Chicago Press Aldrich DP, Meyer MA (2015) Social capital and community resilience. Am Behav Sci 59(2):254– 269. https://doi.org/10.1177/0002764214550299 Australian Bureau of Statistics (2018) Technical Paper Socio-Economic Indexes for Areas (SEIFA) 2016 Catalogue No. 2033.0.55.001 https://www.ausstats.abs.gov.au/Ausstats/subscriber.nsf/0/ 756EE3DBEFA869EFCA258259000BA746/$File/SEIFA%202016%20Technical%20Paper. pdf Australian Business Roundtable for Disaster Resilience and Safer Communities (2016) The economic cost of the social impact of natural disasters. http://australianbusinessroundtable.com. au/assets/documents/Report%20-%20Social%20costs/Report%20-%20The%20economic%20c ost%20of%20the%20social%20impact%20of%20natural%20disasters.pdf Bischeri C (2015) A cyclone-proof community centre for Atherton: tropical monumentality to enable resilience in far North Queensland communities. MPhil Thesis, School of Architecture, The University of Queensland. https://doi.org/10.14264/uql.2015.839 Bosman C, Dedekorkut-Howes A, Leach A (2016) Off the plan : the urbanisation of the gold coast. CSIRO Publishing, Clayton, Vic https://search-ebscohost-com.libraryproxy.griffith.edu.au/login. aspx?direct=true&db=nlebk&AN=1164333&site=ehost-live&scope=site Bridges TS, Wagner PA, Burks-Copes KA, et al. (2015) Use of natural and naturebased features for coastal resilience. US Army Corps of Engineers, Washington, DC. www.nad.usace.army.mil/Portals/40/docs/NACCS/NNBF%20FINAL.pdf Cazenave A, Llovel W (2010) Contemporary sea level rise. Annu Rev Marine Sci 2:45–173 Cutter SL et al (2008) A place-based model for understanding community resilience to natural disaster, Global Environ Change 18 da Cunha D (2019) The Jungle’s Call Harvard Design Magazine No. 45/ Into the Woods http:// www.harvarddesignmagazine.org/issues/45/the-jungles-call Doty DH, Glick WH (1994) Typologies as a unique form of the-ory building: toward improved understanding and modeling. Acad Manage Rev 19:230 Dupre K, Bischeri C (2019) The architecture of resilience in rural towns. Archnet-IJAR. https://doi. org/10.1108/ARCH-07-2019-0178 Flora CB, Flora JL, Gasteyer SP (2015) In: Rural communities: legacy and change, Routledge Goad P (1997) “4.4 The gold coast: architecture and planning. In: Marquis-Kyle AL (ed) Henshall Hansen Associates, Context, HJM, and Staddon Consulting.“Gold coast urban heritage and character study,” prepared for Gold Coast City Council Hill K (2015) Coastal infrastructure: a typology for the next century of adaptation to sea-level rise. Front Ecol Environ 13(9):468–476. https://doi.org/10.1890/150088 Intergovernmental Panel on Climate Change (2012) Managing the risks of extreme events and disasters to advance climate change adaptation A special report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, UK, New York, NY, USA, p 582 Kopp RE, Horton RM, Little CM, Mitrovica JX, Oppenheimer M, Rasmussen DJ, Strauss BH, Tebaldi C (2014) Probabilistic 21st and 22nd century sea-level projections at a global network of tide-gauge sites. Earth’s Future 2(8):383–406 Kulp SA, Strauss BH (2019) New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding. Nature Commun 10:4844. https://doi.org/10.1038/s41467-019-12808-z Lawler A (2011) Did the first cities grow from marshes? Science 331:2011. https://doi.org/10.1126/ science.331.6014.141 Lynch K (1990) In: Michael S (ed) Wasting away, San Francisco, Sierra Club Books Lu D, Flavelle C (2019) Rising seas will erase more cities by 2050, New Research Shows, The New York Times https://nyti.ms/2NkOqOQ Leach A (2018) Gold coast: city and architecture. Lund Humphries, London

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Mathur A, da Cunha D, Squier-Roper C, Laird Prentice G, Weiner MJ (2014) Turning the frontier Norfolk and Hapton roads, Virginia. In: Structure of coastal resilience, Phase 1 context, site, and vulnerability analysis Mileti DS, Gailus JL (2005) Sustainable development and hazards mitigation in the United States: disasters by design revisited. Mitigation and adaptation strategies for global change (3) Nicholls RJ, Cazenave A (2010) Sea-level rise and its impact on coastal zones. Science 328:517– 1520 Nordenson CS, Nordenson G, Chapman J (2018) Structures of coastal resilience. Island Press, Washington Oilier CD (1982) The Great escarpment of eastern Australia: tectonic and geomorphic significance. J Geol Soc Aust 29(1–2):13–23. https://doi.org/10.1080/00167618208729190 Pournelle JT (2003) The littoral foundations of the Uruk State: using satellite photography toward a new understanding Of 5th/4th millenium BCE landscapes in the Warka survey area, Iraq. In: Gheorghiu D (ed) Chalcolithic and early bronze age hydrostrategies. Archaeopress, Oxford, pp 5–23 Pournelle JT (2007) KLM to CORONA: a bird’s-eye view of cultural ecology and early mesopotamian urbanization. In: Stone EC (ed) Settlement and society: essays dedicated to Robert McCormick Adams. Cotsen Institute of Archaeology Press at UCLA, Los Angeles, pp 29–62 Queensland Statistician’s Office Queensland Government projections edition (2018). https://www. qgso.qld.gov.au/statistics/theme/population/population-projections/regions#current-release-qldpopulation-projections-region-reports-2018-edn Sherrieb K, Norris FH, Galea S (2010) Measuring capacities for community resilience. Soc Indic Res 99:2 Vale J, Campanella TJ (2005) Axioms of resilience. In: Lawrence J V, Thomas JC (ed) The resilient city. how modern cities recover from disaster, Oxford University Press, Oxford, New York Woolcock M (2002). Social capital in theory and practice: reducing poverty by building partnership between states, markets and civil society. In: Social capital and poverty reduction: which role for civil society organizations and the State? UNESCO, France, pp 20–44

Cecilia Bischeri Cecilia Bischeri has been specialising in architectural design and its integration with the urban forms since 2006. She has been interested in developing this subject coupling theoretical and applied research. Concurrently, she has been involved in architectural education and has lectured design in Italy and Australia. Cecilia’s main areas of interest regard architectural projects that ground their strengths in connecting the technical requirements of large-scale projects with the provision of a societal dimension for the targeted community. Through the integrative approach of urban and architectural design, the rehabilitation of socially disadvantaged communities and the provision of ameliorative conditions for accelerating the recovery of communities threatened by natural disasters constitute the main body of her work. Cecilia is the co-founder and Head at the Architecture Et cetera Lab. The AEc Lab provides a productive forum for the overlap of academia and architectural practice via the production of practice-based research. Cecilia’s design projects have been shortlisted for international architectural prizes, published and part of expositions in Italy and China. Cecilia is a registered architect.

When It’s Time to Let Go: Re-Imagining Coastal Urban Living in the Face of Rising Seas Elnaz Torabi and Aysin Dedekorkut-Howes

Abstract Sea cities are at the forefront of climate change. Globally, the developed coastline of many cities is at high risk of sea level rise, coastal flooding, and storm surge. Such risks, however, can turn into important opportunities for re-imagining the future of cities and their resilience and sustainability. Despite being controversial, unsettlement, re-settlement, retreat, temporary and permanent relocation, and climigration are concepts that are rapidly becoming an inevitable urban policy and planning consideration. Yet, the idea of a nomadic city, a city that moves, is not new. In fact, the oldest forms of human adaptation to coastal hazards have been through relocation to higher grounds. While temporary forms of relocation have long been prominent in disaster risk reduction efforts, permanent retreat and relocation of urban communities are increasingly becoming critical discussions in climate change adaptation. This chapter focuses on urban resilience to coastal hazards and explores strategies ranging from temporary retreat and managed retreat to migration as a land use policy that can create transformative opportunities for adaptation and re-imagines the future of sea cities in a changing climate. Case studies from around the world are presented, exploring the potential of policy responses as well as the key barriers and drivers for their implementation.

1 Introduction The increasing impacts of climate change put pressure on many cities around the world that are already dealing with urbanisation and rapid population growth issues. Today, nearly half (44%) of the world’s population lives near the coast (United Nations n.d.). Coastal hazards including flooding triggered by sea level rise and increased frequency/intensity of storm surge and cyclones will impact many cities E. Torabi (B) · A. Dedekorkut-Howes Griffith University, Gold Coast, Australia e-mail: [email protected] A. Dedekorkut-Howes e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 J. Baumeister et al. (eds.), SeaCities, Cities Research Series, https://doi.org/10.1007/978-981-15-8748-1_3

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(IPCC 2018). In response, cities will need to build their resilience and adapt to the impacts of climate change. Adaptation is defined as “the process of adjustment to actual or expected climate and its effects” in order to moderate harm and exploit beneficial opportunities (IPCC 2014: 1785), while resilience is the capacity of a city to not only return back and restore its previous functions, but also adjust to change (for example by building back better) and/or transform the way it deals with the impacts of hazards (Rockefeller Foundation n.d.; Torabi 2017). Traditionally, cities have built their resilience and adapted to the impacts of disasters by protecting the vulnerable areas where population, economic activity, and natural resources are located, accommodating the impacts by enhancing the capacity of the natural and built environment and people to deal with the impacts while continuing to use vulnerable areas, and/or retreating people and structures from vulnerable areas via temporary or permanent relocation to safer areas (Dronkers and Mulder 1990). There are arguments for or against each strategy. Protection and defence via engineering structures have been the typical planning responses for many major cities around the world as they are easier to implement and do not disrupt the existing institutional and social contexts (Dedekorkut-Howes et al. 2020b). However, engineering solutions are only as good as their design benchmarks and protect for the short-term. Peterson (2019: 203) warns against planning for individual temporary hazards “rather than the combined effect of more extensive storm surges followed by permanent inundation of increasing amounts of coastal land” and deems attempts at defence a “losing battle” which will only incur further expense of removal in the long run. Dedekorkut-Howes et al. (2020b) agree that retreat will eventually become inevitable for some cities as they cannot be defended indefinitely. According to Siders et al. (2019: 761) “the question is no longer whether some communities will retreat— moving people and assets out of harm’s way—but why, where, when, and how they will retreat.” Cities increasingly need to recognise the need to consider other options including a shift from fighting water to living with it (Rijke et al. 2012). Considering the increasing cost of investment in protection and accommodation strategies (see Donner and Webber 2014), many governments around the world are considering retreat as a viable strategy for the long-term (Dedekorkut-Howes et al. 2020b; Hanna et al. 2020; Hino et al. 2017; Peterson 2019). The retreat strategy applies to a wide range of risks including those associated with sea level rise and coastal flooding, inland flooding, bushfires, and landslides. Retreat also spans across different spatio-temporal scales, involving planned or managed relocation of entire communities, strategic relocation of critical infrastructure, and/or more assetbased responses (Dedekorkut-Howes et al. 2020b; Hanna et al. 2019, 2020; Tadgell et al. 2018). Accordingly, different terminology has been used in framing retreat in urban practice, policy, and research including relocation or realignment; planned or managed retreat; unsettlement, resettlement, migration, abandonment (DedekorkutHowes et al. 2020b; Hanna et al. 2019), or as Matthews and Potts (2018) term it climigration (climate-related immigration and displacement). King (2017: 66–67) distinguishes between relocation and resettlement in that the former is “the ad hoc

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migration of people” whereas the latter denotes “the permanent or long-term movement of a community from one site to another”, and in this sense, resettlement is often the preferred option. The various forms of retreat can be categorised as: (1) vertical retreat which involves elevating structures, (2) engineered retreat which involves land reclamation and filling, (3) temporary relocation during hazards, (4) horizontal planned retreat or managed realignment involving moving permanently to higher land, and (5) migration which involves permanent abandonment of an area (DedekorkutHowes et al. 2020b). Peterson (2019: 204) distinguishes between tactical retreat which may involve “relocating buildings landward on the same property” from larger scale strategic relocation which relocates “coastal neighborhoods, infrastructure, communities, or ecosystems to new, safer sites”. While retreat can enhance the natural coastal processes and is less costly in some cases compared to hard protection (Abel et al. 2011; Harman et al. 2013), it is still a controversial “dirty word” or a “last resort” in planning and decision making, sometimes considered to be surrender or defeat in the fight against climate change. For example, the negative connotations of the term retreat have led to the use of “managed realignment” as a more politically acceptable term in countries such as the UK (Harman et al. 2013; Pethick 2002). The implications of retreat can be very complex, involving difficult decisions. It will require significant resources, communities will lose their homes and neighbourhoods, and there will be interruptions to business and the economy (Lonsdale et al. 2008; Scott et al. 2012). Some view retreat as an unsuitable option for developed urban areas and argue that it can lead to inequality by disproportionately affecting the community, and cause loss of heritage in areas of historical significance (Harman et al. 2013; Lonsdale et al. 2008). There are several barriers to implementation of managed retreat. For instance, existing settlement patterns and lack of suitable land for relocation can be a physical limitation (Harman et al. 2013; Munji et al. 2013; Primo 1997; Scott et al. 2012). Retreat can lead to the clearing of more mangroves and trigger environmental problems (Munji et al. 2013). It is also very likely to result in major legal disputes and have considerable impact on property values (O’Donnell 2019; Scott et al. 2012). Land use controls that prohibit or limit new development in high risk areas can be challenged in the courts as the “taking” of private land and create land tenure and liability issues for local governments (Dedekorkut-Howes et al. 2020b; Primo 1997). The socio-political cost of retreat is high, making it a publicly unacceptable option (Harman et al. 2013; Lonsdale et al. 2008; Sahin et al. 2013). This is mainly due to communities’ desire to live close to water (Torabi et al. 2018) and attachment to their existing lifestyles and cultural heritage (Donner and Webber 2014; Douglas et al. 2012; Primo 1997). The attachment of a community to a place is closely linked to sense of pride and belonging to a community and considered to be the most powerful contributor to a final decision regarding migration and retreat (Jamero et al. 2017). It is important to consider the socioeconomic impacts of population dispersal and mixing as part of retreat due to cultural perception of land loss and community preference for in situ (structural) adaptation options (Harman et al. 2013;

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Lonsdale et al. 2008). There are also negative political implications for land use planning, as local governments are perceived to be withholding tenable land from the market (Alexander et al. 2012). Wealthy property owners want to build along the coasts and politicians waver between managing community demand and responding to increasing coastal risks. This translates into significant financial burden on the community (Harman et al. 2013). Yet, retreat also provides unique opportunities for re-imagining the future of cities in the age of climate change and resource depletion that are so far unexplored (Siders et al. 2019; Black et al. 2011). Many cities around the world have to deal with the legacy development and infrastructure that have been laid out without any consideration of future hazards and climate change. Retreat can provide a second chance for good planning and undoing past mistakes. This chapter focuses on urban resilience to coastal hazards and explores strategies ranging from temporary retreat and managed retreat to migration as a land use policy that can create transformative opportunities for adaptation and re-imagines the future of sea cities in a changing climate.

2 Living Harmoniously with Water Relocation to higher grounds is an old form of human adaptation to coastal hazards. This involves relocation to temporary houses or use of relocatable structures for housing that can be easily transferred to higher grounds, as traditionally practiced in many island and delta communities in the Philippines, Federated States of Micronesia, and Indigenous communities in Australia (Primo 1997; Munji et al. 2013; Jamero et al. 2017). Historically, some sea nomad communities such as the Bajo in Southeast Sulawesi, Indonesia have also spent their entire lives on houseboats (Kusuma et al. 2017). Temporary relocation allows communities to retain temporary houses on the lowlying areas for their livelihood, while using permanent houses on the relocated areas during natural hazards. The underground cities of Cappadocia in Turkey dating back to 1200 BC provide an interesting example of temporary resettlement. They were designed to serve as temporary shelter to tens of thousands of people during enemy invasions (Çiner and Aydar 2019; Bertini 2010). While temporary relocation has long been prominent in disaster risk reduction, permanent retreat and relocation of urban communities are increasingly becoming critical discussions in climate change adaptation (Nalau and Handmer 2018). In the context of western societies, the idea of a nomadic city is also getting traction in the literature. Fry (2011) proposed the concept of the urmadic city to connote urban nomadism and describe non-permanent, moving cities. The idea of an urmadic city, a city that moves, is not new. As opposed to moving existing cities, the urmadic city is designed to move if and when it becomes necessary. These examples throughout history across the globe provide us with opportunities to take lessons from the past to apply them to the future. But this requires the transformation of traditional assumptions that underpin urban planning. Floating houses and neighbourhoods are

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no longer part of a utopian dream, but a possibility of a new form of sustainable urban living, as supported by the United Nations (2019). Yet, a recent systematic review of the literature (Dedekorkut-Howes et al. 2020b) shows a gap in research on the complexities of decision making and planning in this context.

3 Managed Retreat and Resettlement There are several examples of managed retreat and resettlement projects across the world, both successful and unsuccessful. Here we provide a brief overview of some of them focusing on barriers and drivers of their implementation and opportunities they provide.

3.1 Australia With 85% of its population living in coastal areas Australia is extremely exposed to the impacts of climate change, yet despite the urgency of the matter, it does not have a national coastal policy. The lack of leadership from the national level had made coastal adaptation a responsibility of the states and territories, leading to a variety of inconsistent responses (Howes and Dedekorkut-Howes 2016). A review of the coastal policies and plans of all Australian states and territories shows that while some states such as South and Western Australia provide more policy guidance on retreat at higher strategic level there is little on implementation (Dedekorkut-Howes et al. 2020a). Managed retreat has been implemented in Australia in several cases, in less populated areas (towns) and usually as an ad hoc response to a disaster. One well-known case of failure to retreat is the town of Byron Bay in New South Wales, Australia. The significance of this case relates to its demonstration of the critical role of the community for implementation of managed retreat policies. In response to coastal storms in 1970, the local council adopted a managed retreat policy in 1988, which received significant community backlash (England 2013; Harman et al. 2013). In 2009, coastal storms caused severe damage to private property along the beach. Despite the Council’s plans for retreat of property and refusal to reinstate existing sandbag walls, in a legal challenge the community demanded action from the Council to reinstate the sandbags to continue to live in the same area (Leitch 2009). Ironically, a few years later, the continued exposure of the community led the Council to consider more engineering protection measures such as seawalls to defend existing settlements, much like the Gold Coast across the state border (Torabi et al. 2017a). This decision faced significant backlash from the local community that demanded the public amenity of the beach (Lovejoy 2015; O’Donnell 2016). Similar resistance by the community to government initiatives of retreat was also experienced at Smith Island in the Chesapeake Bay in the United States of America (US) after hurricane

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Fig. 3.1 The central pacific island of Tarawa in Kiribati (Government of Kiribati 2005, creative commons attribution 3.0 unported (https://creativecommons.org/licenses/by/3.0/deed.en))

Sandy causing tens of millions of dollars to be committed to protection (Peterson 2019). The island nation of Kiribati (Fig. 3.1) provides another example of backing away from proactive relocation despite previously purchasing land in Fiji for planned resettlement (Walker 2017). On the opposite side of the coin, managed retreat has proved to be successful where appropriate institutional setting is in place and the affected community is properly engaged in the process. The town of Grantham in Queensland was hit hard by flash flooding in 2011 (Fig. 3.2). After the floods the government implemented a land swap strategy to facilitate the relocation of the community. The local government in Grantham purchased a parcel of land on higher ground near the existing flood affected town. Through communication of its land swap strategy by using maps and engaging with the community, the local council facilitated the relocation of the entire community. The proximity of the new area to the existing flood affected community proved helpful as it facilitated engagement: people could see what the new estate looked like and were more interested in the program (Simmonds 2020). Grantham’s experience highlights the importance of existing planning regulations which can hinder action, local political leadership, collaboration between all sectors involved, community participation, and ongoing assessments for the success of resettlement process (Okada et al. 2014; Sipe and Vella 2014). However, the more common approach in Australia is relocation through voluntary buy-back schemes particularly after disasters (King et al. 2014).

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Fig. 3.2 Motor vehicles and motorboat colliding with the railway bridge during the floods in Grantham, Queensland, 2011 (Geoff Purton, John Oxley Library, State Library of Queensland, Image No: 28510-0145-0018)

3.2 The United States Much like Australia, the US is highly exposed to coastal impacts of climate change. In the US flood management has historically focused on enabling people and infrastructure to remain in the same area. Unlike Australia, however, the US has the longestrunning programs of managed retreat globally, driven by its national government (Hino et al. 2017). Voluntary buyouts of flood prone properties funded by US federal agencies, especially the Federal Emergency Management Agency (FEMA), underpins the country’s approach to retreat (Dyckman et al. 2014). There has, however, been significant equity concerns around managed retreat in the US. (Siders et al. 2019). A recent review of FEMA-funded voluntary buyouts by Mach et al. (2019) showed that local governments in counties with higher population and income were more likely to administer buyouts, whereas within cities the buyouts were concentrated in more socially vulnerable neighbourhoods. There are examples such as Soldiers Grove, Wisconsin where managed retreat created opportunities. The deliberate relocation of the business centre of the city away from the river and closer to the highway in 1978 created economic opportunities for a city that is now known as a Solar Town (Siders et al. 2019; David and Mayer 1984). In San Francisco’s Ocean Beach, efforts are under way via the Ocean Beach Master Plan (2012) to address sea level rise, protect existing infrastructure, restore coastal processes, and improve public access to the beach. An important part of the masterplan is the rerouting of

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Fig. 3.3 Artist’s sketch of Ocean view master plan’s vision (Courtesy of SPUR and AECOM)

parts of the Great Highway. Retreat of the existing road in this case, combined with other measures such as asphalt overlays to redirect water runoff and sewer/drainage improvements, is used as an opportunity to improve public access (pedestrian and bicycle) and connections to the beach (SPUR 2012) as shown in Fig. 3.3. The fourth National Climate Assessment (USGCRP 2018: 1329) remarked that “in all but the very lowest sea level rise projections, retreat will become an unavoidable option in some areas along the U.S. coastline” but acknowledged that “the potential need for millions of people and billions of dollars of coastal infrastructure to be relocated in the future creates challenging legal, financial, and equity issues that have not yet been addressed.” So far, the examples of managed retreat are small scale such as the relocation of a bike path and parking lot inland in Surfers Point, Ventura, CA (Kochnower et al. 2015). An example of community resettlement is the Biloxi-Chitimacha-Choctaw Tribe who reside in Isle de Jean Charles in southeastern Louisiana. The ideal resettlement scenario produced by the community highlight the opportunities provided by resettlement: “The residents envision a sustainable community that utilizes ground-breaking technology and resilience measures while integrating the history, traditions, and culture of the Biloxi-Chitimacha-Choctaw tribe” (King 2017: 313). The features of the new community include stormwater detention in community parks, treating water as a resource through family gardens, water management technology, and strategic tree planting and forest and water features that allow for crawfish ponds and migratory bird sanctuaries. The success of the resettlement depends on it being community-led and voluntary. So far, the state of Louisiana has named the master planner of the project and selected a site approximately 40 miles northwest of the Isle de Jean Charles (Crepelle 2018). However, the project is not without its critics. Crepelle (2018) questions why the resettlement funding cannot be used for restoration and erosion prevention and Marino (2018) suggests that Isle de Jean Charles’ exclusion from the levee project due to the cost-benefit analysis may have been a politically sanctioned sacrifice. Jessee (2020) reports that the State’s recent redefinition of the scope of the resettlement and lack of

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commitment to the existing tribal vision has confirmed the fears of the community that it was turning the tribal resettlement into a subdivision. On a larger scale, Hawaii is in the early stages of exploring the feasibility and implications of managed retreat (OP-CZM 2019). The Office of Planning’s project report found that managed retreat is more likely after a catastrophic event (as in the case of Australia’s Grantham) when resources and the resulting political and social will to relocate are more plentiful and urgent. Yet, it is currently not possible to develop a step-by-step plan to implement managed retreat given the various unknowns and competing priorities (OP-CZM 2019).

3.3 The Netherlands The Netherlands is the most famous example of a country with a long history of living with water, implementing multiple managed retreat strategies including the realignment of the shoreline to create space for coastal habitat development and a natural buffer zone for flood protection (Stronkhurst and Mulder 2014). The country’s Room for the River program focused on strategic retreat and removed human-built barriers, reshaping landscapes at more than 30 locations around the country. As part of this program and through extensive consultation with the community, a managed retreat strategy was pursued to lower the existing dikes in De Noordwaard while 75 households were resettled elsewhere in elevated mounds or outside the area (Rijke et al. 2012; Schut et al. 2010; Hino et al. 2017). In this case, residents who initially opposed retreat came around after several repeated inundation events. The project created several opportunities for the landscape, housing, and the agricultural businesses in the area including nature, economic activity, and recreation. The retreat strategy in this case was combined with measures to accommodate the impacts of flooding including safe in situ housing opportunities, evacuation guidelines, construction of a high-water channel to drain large volumes of water to the sea, building higher quays for more sustainable agriculture practices, as noted by the Directorate-General for Public Works and Water Management (Rijkswaterstaat n.d.). A more urban example from the Room for the River program is Nijmegen, one of the Netherlands’ oldest cities. The city’s high-density centre is located in close proximity to the Waal River, extremely exposed to flooding. Here the development along the river did not leave any space to set back from the river or bulk up seawalls. In close collaboration with the residents, the government successfully bought 50 homes, using the space to move the defence structures inland and create a recreational space (Baurick 2020).

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3.4 The United Kingdom One retreat approach is to provide compensation (or support) for private owners whose homes are threatened. Through the UK Coastal Change Pathfinder Programme, five local councils relocated or bought out households at high risk from coastal hazards. Between 2009 and 2011, the programme funded pilot projects and bought out properties, relocating around ten households in different communities (OECD 2019). The North Norfolk District Council was one of the five councils in the UK to receive major funding (£3 million) in 2009–10 under the programme (DEFRA 2012). Owners of the nine houses at immediate risk of coastal hazards were paid a market value. The project initially planned to test the strategy of “buy-andlease back”, but ultimately this was not pursued due to lack of sufficient funding and perceived financial risk to the Council. This project is reported to have increased the Council’s understanding of coastal management strategies and created a sense of community and cohesion (DEFRA 2012). Currently the Environment Agency and local councils are developing Shoreline Management Plans (SMPs) in England and Wales to manage the threat of coastal change (Environment Agency 2019). These include “holding the line” policies which protect settlements and infrastructure with hard defences either for part of this century or all the way to the end of the century with an estimated implementation cost of £18–30 billion. However, a recent report by the UK’s Committee on Climate Change (2018) suggests that this policy is for the most part not cost-beneficial, thus unlikely to get funded raising the need for realistic plans to adapt. The Draft National Flood and Coastal Erosion Risk Management Strategy for England accepts that some areas will flood and promotes managed realignment in areas of high flood risk from rivers. The 2012 Shoreline Management Plan for the area encompassing 600household village of Fairbourne in Wales (Fig. 3.4) has recommended realignment of the coast and eventual decommissioning of Fairbourne eventually prompting lawsuits from residents who argued that the value of their properties decreased (Buser 2020, Peterson 2019). This case of the first and largest UK community to be abandoned also highlights the importance of involving affected residents in the planning process early and in meaningful ways and the need for a robust communication plan that involves the media (Buser 2020).

3.5 New Zealand In line with the IPCC recommendations, adaptation strategies were integrated in the New Zealand Coastal Policy Statement, which provides a national policy direction for coastal management. The policy focuses on managed retreat “by relocation or removal of existing structures or their abandonment in extreme circumstances, and designing for relocatability or recoverability from hazard events” (Department of Conservation 2010: 24). Despite being controversial and facing opposition from the

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Fig. 3.4 Beach at Fairbourne showing the dragon’s teeth sea defences, 2011 (cc-by-sa/2.0 - © SMJ - geograph.org.uk/p/1459592)

affected communities, managed retreat has been implemented by some local councils in New Zealand (Bloomfield 2018). Yet the path towards retreat and relocation of communities has not always been clear. A case in point is Matat¯a, a town in the Bay of Plenty in the North Island of New Zealand hit by debris flows in 2005 after exceptionally heavy rainfall (Fig. 3.5). In the absence of a guiding framework, regulations and the necessary resources, the local council faced significant challenges in managed retreat of affected properties. This resulted in disputes between residents and local government as well as trauma and stress on the community and the officers involved (Hanna et al. 2020). After 14 years, and while some residents continued to be exposed to risk, the Whakat¯ane District Council, the Bay of Plenty Regional Council, and the Department of Internal Affairs agreed on a joint funding for property acquisition in this area. Yet the ad hoc approach to managed retreat has been criticised as being “disruptive and inequitable” resulting in a fragmented risk management approach (Hanna et al. 2020). A successful case of retreat, on the other hand, was carried out by the Waitakere City Council in Auckland. In 2002, the Council developed the Project Twin Streams, running for 10 years to reduce flood risk and improve ecological functioning of the waterways (Bell et al. 2017). Rather than using compulsory acquisition of land through the Public Works Act 1981, the council adopted a voluntary buy back approach through an inclusive participatory process engaging property owners and community representatives such as politicians as well as the M¯aori. As a result, 78 full and 78 partial purchases of properties were successfully negotiated

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Fig. 3.5 Debris flow in Matat¯a in May 2005 (Courtesy of Whakat¯ane Beacon)

to allow for floodplain redesign, linking managed retreat objectives with broader environmental, social, economic, and cultural goals (Bell et al. 2017). In this case, managed retreat created an important opportunity to strengthen the social fabric of the community by providing new public infrastructure (parks, cycleways, and walkways) and accommodating the needs of those who moved to other areas (Vandenbeld and Macdonald 2013). This was in the main achieved by the effective and efficient approach of the Council to engagement by building on the local knowledge of the affected people, having extended periods of engagement to accommodate people’s needs, and negotiating equitable and individualised solutions (Bell et al. 2017).

4 Opportunities: Re-Imagining the Future of Sea Cities in a Changing Climate Fighting with the ocean is a losing battle. Managed retreat is a promising but controversial approach to adaptation. In theory, the idea of removing people and property out of the harm’s way is a no regrets best practice approach to address sea level rise and coastal flooding. However, in practice it is politically sensitive and contentious. To make the technically sound solutions politically acceptable, managed retreat policy and practice needs to be better informed. Managed retreat can create many opportunities for the community. For instance, it can provide funding opportunities for the people who want to leave but cannot

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afford to do so (Siders et al. 2019). The abandoned areas can then be used to restore the natural amenity of the coastline, create opportunities for absorbing flood waters, or can be used as public amenity spaces (Dedekorkut-Howes et al. 2020b; Siders et al. 2019). Above all, managed retreat is an opportunity for social, economic, and ecological transformation and new beginnings (Freudenberg et al. 2016; Siders et al. 2019). Realising the opportunities provided by managed retreat requires a transformational approach to adaptation, adding long-term innovative approaches to change the existing ways of life and practices (Matyas and Pelling 2015, Torabi et al. 2018). This approach is underpinned by a change to embed long-term planning, proactive social learning, critical re-appraisal of the economy, fostering creativity and openness, and incorporating future uncertainty in decision making (Restemeyer et al. 2015; Tchakert and Dietrich 2010). There is an increasing need for embedding managed retreat as a viable option in long-term strategic planning. Siders et al. (2019) emphasise the importance of strategic, managed retreat rather than ad hoc reactive actions to ensure opportunities to contribute to broader societal goals (such as sustainability) and economic development are not missed. Key dimensions of such strategic retreat would include decision-making and planning at larger geographic and temporal scales; involvement of multiple agencies and jurisdictions; addressing of multiple hazards; and integration into planning for economic, social, and environmental goals. Ryan et al. (2015) develop five key principles to govern the large-scale relocation of jobs and housing: (1) out of harm’s way, (2) minimise stress, (3) receiving capacity, (4) build it back better, and (5) feasibility of implementation. Two of these principles illustrate the opportunities provided by relocation. Careful selection of relocation sites would not only protect them from risk of flooding but also other risk factors such as steep slopes, contaminated brownfields, polluted areas, and areas adjacent to heavy industry. Relocation also provides the opportunity to build back better where a holistic plan can be prepared to consider all aspects of sustainable development from energy and water footprints of settlements to opportunities for more active and public transport. Managed retreat can be a catalyst for a resilient and sustainable future, one that includes water sensitive and smart cities, supported by blue-green infrastructure, and providing equitable opportunities for everyone in the city. To be effective managed retreat needs to be implemented on a larger scale, as the retreat of an isolated section of the coast can increase erosion in the remainder of the system, especially if constrained by coastal defence structures (French 2008; Pethick 1993). Often the focus on logistics of moving people and settlements as an ad hoc response to a disaster can undermine the strategic direction and benefit from these opportunities in the longer-term (Siders et al. 2019). Effective governance and management are critical for administering retreat. In Peru, for example, due to limited institutional capacity to ensure the sustainability of the changes, residents of flood prone areas returned to their original housing (Lavell 2016). Such longterm strategic planning needs to be complemented by a comprehensive community engagement for the success of managed retreat (Abel et al. 2011; Alexander et al. 2012). This creates opportunities to not only inform and engage the community about the change process, but also shifts the negative connotation of retreat to a positive

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experience by strengthening the sense of community and creating a common purpose (Siders et al. 2019). The availability of financial resources also plays a big role. For example, retreat of communities can depend on the possibility of obtaining low priced housing in new areas (Douglas et al. 2012; Jamero et al. 2017) and availability of jobs can directly impact the willingness of a community to migrate (Donner and Webber 2014). As the examples in this chapter show, there is also a need for a tailored approach to every context. For instance, relocation of inland communities (in most cases to similar neighbourhoods) is considered to be less contentious compared to the relocation of coastal communities that might lose their immediate connection with the coast (Bloomfield 2018). Several financial and regulatory tools can facilitate the process of managed retreat and exploiting opportunities. These include land use planning, market-based incentives/disincentives, and community engagement (Dedekorkut-Howes et al. 2020b; Peterson 2019). Land use planning includes zoning regulations and overlays requiring increased buffers, setback, and density conditions that can limit development of high-risk areas in cities (Susskind 2010; Harman et al. 2013). Planning policies can facilitate phasing out existing development and/or promote more conditional development options (Frazier et al. 2010). Temporary development (such as ephemeral buildings) can be built in high-risk areas with conditions to abandon properties on specific timeframes or when the risk is too high (Harman et al. 2013). Incentives include facilitating land swaps that trade ownership of developed areas near the coast via transferrable development rights for land owned by the government located outside risk zones (Frazier et al. 2010; Susskind 2010), and providing legal foundations for government buy-outs such as establishing and funding a buy-out program as discussed in the case studies. Rolling conservation easement, transfer of development rights, mandatory disclosure of risk in real estate transactions are important policy tools in this context (Alexander et al. 2012; Peterson 2019; Siders et al. 2019; Susskind 2010).

5 Conclusions To be effective, a managed retreat policy needs to be supported by government leadership at all levels (Taylor et al. 2013; Peterson 2019). Higher levels of government play an important role as local governments do not necessarily have the capability to manage legal, political, and financial risks associated with managed retreat (Harman et al. 2013). Recently there has been a global call for national level leadership on retreat as an opportunity to redesign underlying norms and infrastrcture of our cities (Siders et al. 2019). In fact, Peterson (2019) believes that a national relocation framework that illustrates the financial infeasibility of structural protection everywhere will improve the chances of relocation to be considered as a policy option. Research also demonstrates that local governments are more likely to act when there are guidance, benchmarks, and requirements from higher level governments (Dedekorkut-Howes et al. 2020b; Dedekorkut Howes and Vickers 2017; Torabi et al. 2017b).

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Yet, such an approach will require significant shifts in institutions and behavioural change to support the transformation. There is a need for a collaboratory and integrated approach to planning, underpinned by reliable and large scale hazard data to better inform decision making. This is an important consideration for sea cities globally, as climate change may cause hazard information, such as local council flood maps, to be dangerously outdated (Meyer 2020). In conclusion, managed retreat will require many difficult decisions to be made, implementation of which will require reconceptualising our relationship with our properties and neighbourhoods (Siders et al. 2019), imagining urmadic cities and communities moving across land and the ocean that are not bounded by land, but on sociocultural values that create communities (Fry 2014).

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E. Torabi and A. Dedekorkut-Howes Elnaz Torabi Dr. Elnaz Torabi is a Lecturer in Environmental Policy/Planning at Griffith University, School of Environment and Science. She is a city planner/architect and has a background in urban and environmental planning research and practice. Her research explores urban resilience and adaptation to climate-related disasters in coastal cities. This research is topical at a time when governments and communities are struggling to effectively respond to future uncertainty and change. Elnaz is affiliated with Griffith’s Cities Research Institute and its Adaptation Science Research theme focusing on planning and decisionmaking for building resilience. Her research interests include water resilient cities, strategic planning, and decision-making processes under uncertainty. Aysin Dedekorkut-Howes Dr. Aysin Dedekorkut-Howes is Program Director of Urban and Environmental Planning and member of the Cities Research Institute at Griffith University. She has a PhD from Florida State University, a Master’s degree from Clemson University, and a Bachelor’s degree from Middle East Technical University in urban and regional planning. She has taught and conducted research in the United States, Turkey, and Australia. Aysin has expertise in environmental planning, natural resource management, governance and collaborative planning, regional planning, and growth management. Her research focuses on climate change adaptation and disaster resilience, water resource management, and urbanisation in subtropical areas and coastal cities. She is the co-editor of the book Off the Plan: The Urbanisation of the Gold Coast.

Lo-TEK: Underwater and Intertidal Nature-Based Technologies Julia Watson, Despina Linaraki, and Avery Robertson

Abstract This chapter considers the underwater and intertidal nature-based technologies of indigenous cultures and explores their innovations as solutions for the impacts of climate change to low-lying coastal areas. Indigenous people have been living with and developing water-responsive infrastructures for generations that engage and support the complex ecosystems they inhabit. Rooted in traditional ecological knowledge, or TEK, these technologies work symbiotically with, rather than against nature, ushering in a more comprehensive approach to underwater and intertidal design. Indigenous peoples’ responses to sea level rise and storm events improve coastal resiliency, yet remain undocumented and unexplored in the evolution of contemporary solutions. This chapter places these technologies in the modern scientific framework, cross-referencing indigenous people’s local nature-based technologies using the five sea level rise response strategies outlined in the Intergovernmental Panel on Climate Change’s 2019 Special Report on the Ocean and Cryosphere in a Changing Climate: protect, accommodate, retreat, advance, and ecosystem-based adaptation. Reframed through an architectural and scientific rather than anthropological lens, the challenges cultures were facing and the resources that were available to them are explored to inform us in designing for global climate resiliency today. Keywords Lo-TEK · TEK · Indigenous · Nature-based solutions · Hybrid technologies · Resilience · Climate change · Coastal resilience · Ecosystem protection · Symbiotic design

J. Watson (B) Graduate School of Design, Harvard University, Cambridge, USA e-mail: [email protected] School of Architecture, Planning and Preservation, Columbia University, New York, USA D. Linaraki SeaCities, Cities Research Institute, Griffith University, Gold Coast, Queensland, Australia e-mail: [email protected] A. Robertson Independent Scholar, New York, USA e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 J. Baumeister et al. (eds.), SeaCities, Cities Research Series, https://doi.org/10.1007/978-981-15-8748-1_4

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1 Changing Grounds Coastlines have been occupied since the time of the earliest settlements for access to trade and resources.1 However, this proximity to water now poses a threat; climate change is forcing us to rethink our relationship with water—as the seas rise, we must adapt. Currently, 11% of the world population lives in coastal areas which are less than ten meters above sea level.2 After unprecedented disasters, the fear of flooding motivates responses to coastal resilience, preferring fortification to accommodation, elevation, or migration. Overwhelmingly homogeneous, high-tech infrastructures are deployed irrespective of local communities and environmental conditions. Designed primarily by and for affluent cities, these single-purpose solutions which are adopted globally as “best practice” are counterintuitively incompatible with local skill sets and ecosystems.3 This chapter challenges the “best practice” narrative by documenting traditional indigenous responses to coastal resilience that instead amplify cultural, ecological, economic, and agricultural resilience. The impacts of climate change to coastal communities, including sea level rise, storm surges, and salination will uniquely, not universally, affect ecosystems, ecosystem services, natural resources, and human systems.4 Avoiding catastrophe will depend largely on the individual responses by communities and local governments. As stated in the United Nations’ Intergovernmental Panel on Climate Change’s Special Report on the Ocean and Cryosphere in a Changing Climate of 2019, “Before technical limits are reached, economic and social limits will be reached because societies are neither economically able nor socially willing to invest in coastal protection.”5 Climate change is predominantly addressed in the aftermath of an environmental disaster, through recovery and resilience efforts by government agencies. In these times of crisis, adopted technologies become market driven as quick solutions are required. In major global cities like New York and Amsterdam, hard infrastructural and technical solutions to coastal resilience are deployed. For other less affluent cities, resilient technologies must take a different approach. The most vulnerable climate crisis communities are often those in impoverished areas or undeveloped nations, which lack the capital and resources needed for hightech, costly, contemporary-resilient infrastructures. These communities are sold a belief that the high-tech solutions of developed cities are superior to their own innovations, even though the latter embody the intelligence of the environments and cultures that have evolved them. This research explores how hybridizing and scaling indigenous coastal, nature-based technologies is both an effective and pragmatic solution to be included in today’s toolkit for resilient design. This chapter examines how systems evolved from traditional ecological knowledge can work as multi-dimensional ecosystem approaches to reducing the impact 1 Nunn

(2007).

2 Oppenheimer

et al. (2019). et al. (2017). 4 See Footnote 2. 5 Ibid. 3 Nunn

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of climate change. Some examples explored include the fish ponds of the Hawaiian people, the Langalanga Islands of the saltwater people on the Solomon Islands, and the taro islets of the Yapese people in Micronesia, all of which function as integral pieces of larger multi-ecosystem scale mitigating interventions. While indigenous peoples’ responses to coastal resilience remain largely unexplored in the search for design solutions, these studies at the material, module, structural, and system scale, which are reframed through an architectural rather than anthropological lens, will inform the future of design for climate resilience.

2 Lo-TEK This chapter retells an ancient mythology—that humankind can and must live symbiotically with nature. Lo-TEK, a term coined by Harvard and Columbia University Lecturer of Urban Design Julia Watson, is identified as resilient infrastructures developed by indigenous people through traditional ecological knowledge (TEK). The movement to bring these innovations to the forefront of the design field counters the idea that Lo-TEK indigenous innovation is low tech: unsophisticated, uncomplicated, and primitive. Instead, Lo-TEK aligns to today’s sustainable values of low energy, low impact, and low cost, while producing complex nature-based innovations that are inherently sustainable. Forming the foundation of indigenous technologies, TEK is a field of study in anthropology defined as a cumulative body of knowledge, practice, and belief, handed down through generations by traditional songs, origin stories, and everyday life. By using TEK, humans have been able to harness the energy of ecosystems and adapt to environmental obstacles using soft and symbiotic living systems. Developed through direct contact with nature, TEK is engineered to sustain, rather than exploit resources. It fosters symbiosis between species, while making biodiversity the building block used to construct sustainable technologies. Lo-TEK is how humans have been dealing with the extremes of the climate for millennia, by harnessing the energy and intelligence of complex ecosystems. It suggests that it is eminently possible to weave ancient knowledge on how to live symbiotically with nature into how we shape the cities of the future, before this wisdom is lost forever. We can rewild our urban landscapes and apply Lo-TEK ecological solutions to sanitation, storm surge, sea level rise, drought, deluge, wildfire, food supply, and fresh drinking water, that have worked for indigenous peoples for thousands of years. Many contemporary green technologies, like green roofs and floating wetlands, have been around for thousands of years, being rediscovered only when packaged as new. The vision for this research is something of the same. By gathering a compendium of indigenous design and innovation, a framework for adaptation and innovation is posed that reroots our very relationship with nature from superior to symbiotic, exploring the intersection of design and radical indigenism. This concept

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takes its name from the Latin derivation of the word “radical”: radix, meaning “root.”6 Radical indigenism, as defined by Princeton Professor and citizen of the Cherokee Nation Eva Marie Garroutte, argues for a rebuilding of knowledge and explores indigenous philosophies capable of generating new knowledge.7 Lo-TEK orients us toward a different mythology of technology found across the globe. It expands the definition of contemporary technology by rebuilding our understanding of climateresilient design using indigenous knowledge and practices that are sustainable, adaptable, and borne out of necessity.

3 Adaptation Pathways Sea level rise is accelerating, prompting designers, scientists, economists, and politicians to ask “how will we survive? and where can we look for solutions?” in a continually shrinking time frame.8 The Netherlands is seen as a nation of leading world experts in keeping the ocean at bay. Since 2010, the country has developed the Delta Programme as a water management and flood mitigation strategy with the goal of keeping ahead of the floods. But different cultures across the globe have formed vastly varied relationships with water that may not be synonymous with the Dutch approach. Nor do they have the resources required to replicate some of the proposed solutions, when local conditions might necessitate unique adaptations. Universally, what works for the Netherlands is taken as the best practice benchmark, but in reality this is only true in specific geopolitical locations. In the book The Collapse of Western Civilisation, American science historian Naomi Oreskes, of Harvard University, and Erik Conway outline a dystopian but scientifically plausible prophecy about the impact of climate change after humanity has failed to effectively curb global warming.9 In this essay, a dystopic future history is imagined in which the Netherlands is the main character, as the Dutch population migrates northward into Germany as the landscape of polders and dikes slowly succumbs to the sea. The essay is not a map of fighting back from an unforeseen environmental catastrophe as is the current climate change approach, but instead shows how the Netherlands could change as a result of gradual developments, rather than major disasters. The essay elucidates an alternative approach to a climate change response where in the face of deep uncertainty a “wait and see” approach to adaptation is taken, until uncertainty is reduced. Protocols around decision making in the face of great uncertainty, especially in the era of climate change, are changing. To support this shift, Marjolijn Haasnoot, an environmental scientist and the founder of the Dynamic Adaptive Policy Pathways approach, advocates an adaptation pathway approach, in which sequences of 6 Hoad

(2003). and Defining (2020). 8 Church et al. (2013). 9 Oreskes and Conway (2013). 7 Garroutte

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linked actions can be implemented as conditions change.10 These adaptation pathways in response to sea level rise are described as four distinct scenarios: defend, surrender, offend, and retreat. Synonymously, the United Nations Intergovernmental Panel on Climate Change’s 2019 Report identifies similar categories: protect, accommodate, advance, and retreat, and a fifth ecosystem-based approach.11 The alternative scenarios described as adaptation pathways expand the climate change conversation beyond simply fighting back. In this chapter, we use these four adaptive scenarios to categorize the underwater and intertidal technologies of indigenous communities. While the use of TEK in empirical science is not new, applying TEK to a scientific framework is. Traditional ecological knowledge is present in the foundation of scientific knowledge today, only remaining uncredited by an inability to ascribe this knowledge to institutionally based criteria.12 Categorizing the following indigenous innovations in accordance with the IPCC’s 2019 Special Report on the Ocean and Cryosphere in a Changing Climate definition of sea level rise responses allows our contemporary-resilient design approaches to embrace TEK. In each scenario, two indigenous innovations found in existence across the globe are described in detail. Lo-TEK: Underwater and Intertidal Nature-based Technologies is a deeper investigation of specifically coastal indigenous technologies.

3.1 Defend/Protect The Netherlands was settled by the Frisians in 400 BCE by building terpenes or mounded villages that were protected from flooding, and long dikes or embankments that prevented inundation. Since then, the Dutch and their ancestors have been working to hold back and reclaim land from the North Sea for over two thousand years.13 According to 2019 IPCC Special Report on the Ocean and Cryosphere in a Changing Climate mentioned above, protection refers to all the strategies that aim to protect the coastal areas, by eliminating the impact of natural hazards.14 Effective protection is provided by coastal ecosystems and sediment-based protection, but the most widely used protection strategies involve hard infrastructures. Contemporary protection structures include breakwaters, sea walls, dikes, and surge barriers. While in the short term these solutions are cost-effective in dense urban areas, hard protection techniques can be expensive to maintain and rebuild, and they can lead to flooding, erosion, and the destruction of alternatively protective ecosystems. For example, if the Netherlands were to continue using current systems for keeping the sea at bay, dikes will need to be raised making the polders behind them deeper, more 10 Haasnoot

et al. (2013). Footnote 2. 12 Ellen et al. (2000). 13 Borger et al. (1998). 14 See Footnote 2. 11 See

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Fig. 1 This world map is indicating the location of the two indigenous technologies that are analyzed below. The first is the Loko i’a kalo, loko wai, loko pu’uone, and loko kuapa Fish Ponds in the Ahupua’a of the Hawaiians, Hawaii, and the second is the Derdernin and Ngurruwarr Fish Traps of the Kaiadilt and Lardil Saltwater People of the Wellesley Islands, Australia

vulnerable, and more expensive to maintain. Higher dikes pose their own problem by preventing natural silting, thereby stopping the delta from being able to grow along with the advancing sea. Even these measures combined in the long term may prove insufficient in preserving the low-lying parts of the Netherlands.15 In the following section, the Loko i’a kalo, loko wai, loko pu’uone, and loko kuapa16 Fish Ponds in the Ahupua’a of the Hawaiians, Hawaii, and the Derderninand NgurruwarrFish Traps of the Kaiadilt and Lardil Saltwater People of the Wellesley Islands, Australia, are explored as nature-based technologies that can inform the development of protective resilient infrastructures today (Fig. 1). Both of these examples contain the base architecture component of a wall combined with a sustainable aquaculture seascape. Unlike contemporary infrastructures and materials, such as reinforced concrete used to construct sea walls, these indigenous structures utilize local materials, implement existing ecosystem offerings such as mangrove roots, oysters, and algae, and opportunistically offer habitat to species that increase the resilience of the system.

15 Schuttenhelm 16 Kikuchi

(2019). (1976).

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Fig. 2 The longest fish pond that currently exists in Hawaii is located at He’eia, Honolulu on the Island of Oahu (Source Google Earth© 2020 Maxar Technologies)

3.1.1

Loko i’a Kalo, Loko Wai, Loko Pu’uone, and Loko Kuapa Fish Ponds in the Ahupua’a of the Hawaiians, Hawaii

The landscapes of the Hawaiian Islands range from barren volcanic mountain tops to highland forests to river valleys ending at the land–sea interface containing farmed land and fish ponds. The Hawaiian people developed a complex land division system, held in trust and controlled by the highest chief or king, dividing up the island, a mokupuni, into ahupua’as along the natural boundaries of the watershed. Each ahupua‘a contained the resources for self-subsistence and encouraged trading from fertile lowlands for farming taro or sweet potato, to koa and other upland trees for timber, to fish ponds located either offshore (Fig. 2) or inland providing fish and salt. Inland villagers exchanged agricultural foods and wood for canoes for fish with the coastal communities.17 Hawaiian fish ponds or loko are enclosed bodies of inland or ocean water. These ponds were an important resource in the ahupua’a system. They belonged to the local chief, an ali‘i, who ruled an ahupua’a. A well-maintained fish pond and water system was a signifier of a healthy community in the ahupua’a.18 The fish ponds are thought to have originated in the fourteenth century, and were mostly built four to six hundred years ago.19 Fish ponds are found both inland and in large expanses of shallow sea extending from the coasts of the islands (Fig. 3). There are four basic 17 Levy

and Chernisky (2005). (2005). 19 See Footnote 16. 18 Joana

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Fig. 3 The divisions in the ahupua’a system are based on the watershed, radiating out to the coast from the mountain and containing multiple ecological zones at different elevations. The fish pond, here of the loko kuapa type, is located at the coast

types of ponds: loko i’a kalo, loko wai, loko kuapa, and loko pu’uone,20 as well as one fish trap: loko ‘umeiki.21 Loko i’a kalo were freshwater inland irrigated agricultural ponds for the farming of fish and of taro (Colocasia esculenta). These ponds, or lo’i, began as shallow depressions that were fed with running water from the mountains, and stocked with fish and food to create the system of aquaculture. The pond’s shallow depth provided excellent conditions for the growth of taro, algae, seaweed, and plankton. Fish then entered directly from the sea through artificial estuaries or were carried in overland by the farmer.22 The fish thrived due to the abundance of food in the pond—and the fish, in turn, provided a plentiful supply of food for the farmers. The loko wai was much closer to the shoreline and would often become brackish from tidal waters, and naturally attract fish from the sea. These were excavated by hand from natural depressions and filled from groundwater springs, aquifers, or diverted streams and rivers. Fish were harvested in these ponds by woven reed nets hala, which were placed across a channel as they migrated back to the sea for spawning.23 The loko kuapa fish ponds were located in shallow coastal areas and had semicircular walls built of lava stone or coral (Fig. 4), kuapa; canals, auwai; and one or more 20 Ibid. 21 Costa-Pierce 22 Ibid. 23 Ibid.

(1987).

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Fig. 4 What remains of the Huilua Fish pond: a rock wall extended into the sea. (Source Bradshaw 2010)

sluice gates, makaha (Fig. 5). These kuapa walls ranged from 46 to 1920 m long, and some were built using coralline algae as a natural cement to strengthen them.24 The auwai were built into the walls, connecting the inner pond with the sea, with a makaha placed in between.25 The makaha had narrow grates which allowed water and young fish to move in where they would feed on seaweed placed in the pond.26 The grates were made of timber, or lama, that were lashed together vertically with crossbeams, separating the vertical beams by 0.5–2.0 cm spaces. When the mature fish attempt to return to the sea to spawn, they are no longer able to pass through the narrow openings and are harvested. A later addition to the canal was a second makaha, which was lowered during the fish’s attempted migration, trapping the fish in the canal for easier harvesting (Fig. 5). The loko pu’uone were coastal brackish water ponds with wide, permeable, irregular walls, or pu’uone, built of mud, sand, and coral. The pond was connected to the ocean by a canal that allowed seawater to enter on a rising tide, and had freshwater inputs from streams, aquifers, and groundwater, producing a brackish water environment similar to an estuary and held a variety of fish species.27 The shoreline fish trap, the loko ‘umeiki, was very similar to the loko kuapa, in the way of being a semicircular stone wall, except that these walls were submerged at high tide and contained many canal-like openings with no makaha. Instead, fish were caught by nets held by fishermen at the openings who caught them with the tide.28 Each fish pond had a 24 Ibid. 25 Ibid. 26 Bond

and Gmirkin (2003). Footnote 21. 28 Ibid. 27 See

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Fig. 5 Gate of the loko kuapa fish pond. The rock wall features a canal with a sluice gate made of lashed timber. This gate has narrow openings which allows smaller fish to enter, where they feed and grow, but does not allow them out once they reach maturity

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Fig. 6 Huilua Fish pond, in Kahana Bay on the Island of Oahu as seen from the Pu’u Manamana Ridge. This is one of the few fish ponds that remain. Source Jesse (2020)

pondkeeper or kia‘i loko who lived nearby to oversee maintenance. The loko kuapa pond additionally had a hala kia’i who had a similar but more protective type role to the kia ‘i loko. In this pond type, simple shacks were placed on the walls adjacent to the makaha areas acting as shelters for the hala kia’i.29 In 1778, three hundred and sixty fish ponds across the Hawaiian Islands supplied the needs of thousands of people. By the early 1900s, as the population of indigenous Hawaiians decreased, fewer than one hundred ponds and traps remained, yet still produced seven hundred thousand pounds of fish yearly. By 2003, only four fish ponds remained (Fig. 6). Many factors contributed to their displacement, including warfare among chiefs who destroyed the fish ponds of enemies, the sandalwood trade which eventually denuded the mountains of trees, causing erosion while simultaneously taking labor from the shoreline, mangrove reforestation that hindered the growth of algae and transformed the ponds into mudflats, natural disaster, disease, land development, and the shift from a subsistence to market economy (Fig. 6).30

3.1.2

Applicability to Contemporary Infrastructures

The fish pond typologies show how coastal infrastructures can be built with local ecology and watershed dynamics. Their effective food production and watershed 29 See

Footnote 16. (2005).

30 Joana

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Fig. 7 Kaiadilt fishing traps at Sweers Island, in Northeast Queensland. Source Google Earth© 2020 Maxar Technologies

management contributed to the success of the indigenous Hawaiian community. The construction of walled ponds also showed how local ecosystems could be used as building materials, such as the colonization of coralline algae to form a jointing concrete and to build productive, aquatic infrastructures. An additional unintended benefit of the coastal fish ponds was a reduction in wave impact and storm surge, which suggests the potential hybridization of wave breaks or dikes with aquaculture systems in contemporary coastal cities for both production and protection.

3.1.3

Derdernin and Ngurruwarr Fish Traps of the Kaiadilt and Lardil Saltwater People of the Wellesley Islands, Australia

The Wellesley Islands, located south of the Gulf of Carpentaria in Northeast Australia, are populated by three aboriginal groups: the Ganggalida of the mainland, the Lardil and Yangkaal of the North Wellesley Islands, and the Kaiadilt of South Wellesley Islands (Fig. 7). Between winter and summer, these groups migrate from inland camps to coastal areas. In Aboriginal mythology, land and marine systems are shaped and built by their mythic ancestor, Marnbil, not by nature.31 They made a clear distinction between the land and the sea (mala). Land, made up of tussock grasslands, eucalyptus woodlands, and scrublands, is known as the “inside country,” and the sea and coastal areas, made up of tidal flats, sandy cheniers, boulder beaches, cliffs, and reefs, are

31 Memmott

et al. (2008).

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Fig. 8 Australian aboriginal fish traps. (Source Reproduced with permission from Reef Catchments (This photograph was taken by Regina Bernard, former Indigenous Project Manager MWINRM Group (Reef Catchments) for the Fishtrap Project 2009, undertaken with the Mackay Whitsunday Isaac Traditional Owner Reference Group))

known as the “outside country.”32 The Lardil and Kaiadilt people who lived on smaller islands both used rock wall fish traps, known as derdernin to the Lardil and ngurruwarr to the Kaiadilt.33 Natural rock formations or reefs were also used as traps, with the construction of these being attributed by the Lardil people to the ancestral god Marnbil.34 Multiple types of rock wall fish traps were constructed, with the derdernin and ngurruwarr used for harvesting at low tide, the baljan for chasing and spearing, and the gated yilin trap for chasing and netting (Fig. 8). Enclosed rock wall fish traps were constructed primarily of rocks, but also utilized the surrounding ecology in the construction. Walls were often built from existing rock pieces or elevated mangroves.35 The layout of rock wall fish traps varied slightly, forming either a Uor a V-like shape (Fig. 9). In the V-shaped trap, which were often linked to form multiple W-like shapes, the point faced the sea and the opening reached the shore. In the V shape, a few rocks at the point could be removed and replaced with a gate, 32 Memmott

and Trigger (1998). Footnote 33. 34 Ibid. 35 Ibid. 33 See

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Fig. 9 In the axonometric, the system is shown as a U shape, with the point facing the sea and the opening reaching the shore. The detail shows the gate that opens and closes to allow fish to go in and out

which was opened when the tide rose allowing fish to enter. When the tide fell, the gate, being tied with mangrove foliage, trapped the fish inside.36 The elaborate gate trap often included a “pocket,” which acted as a pen, to contain fish (Fig. 9). The trap walls were low so that during the high tide, which may rise up to three meters, larger fish, dugongs, and other aquatic creatures were allowed to swim over the rock wall, trapping them within the wall when the tide falls (Fig. 10). The success of a rock wall fish trap was determined by whether they remain stable when hit with the tide. Therefore, when deciding upon a location, the tidal range must be limited and traps positioned on the sheltered side, out of the path of strong, prevailing winds. Oftentimes, the roots of surrounding mangroves grew into the rock wall aiding in its stabilization by reducing some of the tidal force. Fringe reefs, which grow on shallow shores, also functioned like the mangroves, alleviating the tidal force acting on the walls and providing additional stability. Typically, rocks are 36 Ibid.

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Fig. 10 The section shows the wall structure. The total height would be lower than the high tide to allow water to come in. The mangroves enhance the stability of the system by integrating their roots to the structure

twenty centimeters in diameter, and they are stacked to form the wall. The structure has an overall height between fifteen and ninety-seven centimeters and an average width of fifty centimeters. The length can grow up to two hundred and ninety meters (Fig. 10).37 Oysters would grow on the surfaces of the rocks, and mud sediments would pile up against the wall, further strengthening the rock wall itself. There was a symbiotic relationship of stabilization between the rock wall and oysters, as the rock wall provides habitat for oysters to grow on, while the oyster uses calcium carbonate to attach to rocks, which acts as jointing mortar that keeps rocks in place. The oysters form in clusters, creating reefs with older shells. As they die off, the early stage oysters known as spats attach to the older, hollowed shells, growing to contribute to the overall structure (Fig. 10). Fish were also harvested by spearing prior to the trap becoming emptied. One method involved waiting until the tide had fallen below the top of the wall, then herding fish into groups and directing them toward one or more spearsmen by people hitting the surface of the water. Another method was by spearsmen walking along the walls spearing fish as the tide fell. Dugongs, an animal similar to the more commonly known manatee, were also chased by men on rafts into the shallower water where they could be easily speared.38 The major difference between the Lardil and Kaiadilt 37 Kreij 38 See

et al. (2018). Footnote 33.

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traps were that the Kaiadilt traps had bigger paddocks and were built on areas where sea weeds grew. These areas were more attractive to turtles and dugong. The Lardil additionally utilized a series of hibiscus rope nets for hunting dugong. During cool dry seasons, when strong winds occur, inland settlements constructed fish traps in streamlets, which were smaller compared to the coastal rock wall fish traps. To maximize weather conditions in hotter months, settlements were moved to positions along coastal ridges to maximize breeze and access to water making the hunting of dugongs, fish, and turtles easier. Several hundred fish traps are located at over one hundred sites along the island’s coast, with the sandy or muddy surface helping to stabilize the rocks. Communities assisted in the building and repairing of the traps in exchange for the fish caught.39 These fish traps were particularly important for ensuring food security in an environment where tidal surge could destroy other sources of food.

3.1.4

Applicability to Contemporary Infrastructures

The Derdernin and Ngurruwarr Fish Traps are great examples of aquatic wall construction. Fish traps weathered severe storms through a symbiosis between the preferred oysters’ habitat, the wall structure, and the natural production of calcium carbonate by individual oysters upon adhering to a surface. Over time, the walls grew stronger as more calcium carbonate was deposited. Fish traps acted as both an aquaculture infrastructure and a protective wall, acting similar to wave breaker or to a dike. Performing as both a protective and productive infrastructure similar fish pond structures could offer multiple benefits to coastal cities.

3.2 Surrender/Accommodate The second strategy for sea level rise outlined by the IPCC is “surrender” or “accommodate,” which takes the approach to sea level rise of letting water in. This strategy can take place in various scales, methods, and levels of temporality. It can be applied in urban environments through flood zoning restrictions, insurance plans, warning systems, emergency planning, setbacks, and flood barriers. The IPCC’s definition of “accommodation” refers to the redesign of physical and political infrastructure to accommodate sea level rise and reduce vulnerability. In addition to urban flood accommodation measures, strategies include updating building codes, raising buildings on stilts, floating houses and gardens, aquaculture, and adapting to salinity intrusion, though changing crop varieties and land use. In the following section, the Phumdis or Phumshongs of the Manipuri on Lake Loktak, India, and the Ma’a and Mu’ut Taro Gardens and Floating Taro Patches on the islands of Yap and Puluwat, Micronesia (Fig. 11), are explored 39 Rowland

and Ulm (2011).

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Fig. 11 This world map indicates the location of the two indigenous technologies that are analyzed in this section

as adaptive technologies that work similarly to the IPCC strategy of accommodating water, as they are buoyant and employ aquatic vegetation.

3.2.1

Phumdi or Phumshongs of the Manipuri on Lake Loktak, India

Speckled across Lake Loktak, northeast India’s largest freshwater lake are thousands of circular, floating meadows known as phumdis or phumshongs (Fig. 12). Referred as the “lifeline of Manipur,”40 the lake’s ecosystem is a unique biodiversity hotspot and provides many environmental services such as nutrient recycling, water purification, groundwater recharging, and runoff control.41 At a width of nine kilometers and length of eleven, almost seventy percent of the lake’s surface is covered by several thousand floating meadows, which exist only here (Fig. 13).42 The phumdis are used by the local people for constructing artificial floating islands, known as athaphum, topped by huts, phumsang.43 The local Manipuri people create the athaphum artificial circular enclosures out of multiple phumdis for fish farming. These circles reach one hundred meters in diameter and allow thousands of fishermen to catch an average of one thousand, five hundred tons of fish every year (Fig. 14). The athaphum is surrounded with nylon netting that reaches the lake bed, while silt is stirred with 40 UNESCO

(2016). and Singh (2014). 42 Singh and Khundrakpam (2011). 43 Bhardwaj (2017). 41 Rai

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Fig. 12 Multiple phumdis for fish farming, covering a large portion of the Lake Loktak. Source Google Earth© 2020 CNES/Airbus

Fig. 13 Phumdis at Lake Loktak. Source Prasad (2008)

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Fig. 14 Axonometric plan of the phumdi

bamboo poles to reduce oxygen levels in the water, thereby bringing the fish to the surface to be easily caught.44 Phumdi or phumshongs are circular land masses of vegetation, decomposing organic matter, and black soil that has thickened into a solid and spongy form, known as peat. A phumdi is grown when a dense mass of water hyacinth or other organic matter accumulates silt that is suspended in the water. Grasses and other plants grow on this mass and decompose, building up layers of the peat. The soil is composed of organic carbon, nitrogen, and organic mineral matter, at various stages of decomposition.45 The first layer, the root zone, is between zero and fifteen centimeters, the second layer, the mat zone, is twenty-five to sixty-five centimeters, and the lowest layer, made of organic matter, is between zero and twenty-five centimeters (Fig. 15).46 Similar to an iceberg, one-fifth of the structure emerges above water while four-fifths remain submerged below.47 The phumdi can be up to two and a half meters thick, and the high concentration of vegetation matter gives it its buoyancy.48 The phumdi acts as both biofilter and habitat in the aquatic ecosystem. During the dry season, when Loktak Lake’s water level drops, the living roots of the islands can reach the lakebed and absorb essential nutrients, resurfacing after spring (Fig. 16). The largest single mass of phumdis lies in the southeastern part of the lake and covers thirty-eight square kilometers. It is home to the Keibul Lamjao, the world’s only floating national park which was created to preserve the habitat of the endangered 44 Heggen

(2018). Footnote 45. 46 Takhelmayum and Gupta (2011). 47 Singsit (2003). 48 See Footnote 45. 45 See

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Fig. 15 Detail of the structure of the phumdi

Fig. 16 Section of the phumdi

brow-antlered deer, the sangai, Manipur’s state animal that was once thought to be extinct. The phumdi area of the park supports around four hundred species of animals, including the rare Indian python and two hundred species of plants including grass, sedges, ferns, and herbs.49 The phumdi habitat is threatened by the encroachment of humans and livestock, the annual burning of the phumdi by government officials, the inflow of polluted water, and the Ithai Barrage.50 The Ithai Dam was built in the 1980s to provide power for India’s northeast states as well as irrigation and drinking water, yet it has threatened the life of the lake. The lake inflow is fed by almost thirty rivers which contain agricultural chemicals and domestic waste along with high levels of sediment. The only outflow from the lake is through the Ithai Barrage which only releases water.51 Both the river inflow and the dam outflow conditions have contributed environmental problems such as siltation, proliferation of phumdi, eutrophication, prevention of fish 49 Tuboi

et al. (2012). Footnote 47. 51 Ranganathan (2017). 50 See

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spawning, loss of fish biomass and diversity, and ironically, loss of water available for hydraulic power generation. The dam prevents the natural removal of old phumdi, which was typically washed away in monsoon season, while the fertilizer nutrients from the rivers cause an accelerated growth of phumdi, causing a proliferation that is proving harmful to the ecological functions of the lake. The number of phumdi slows the flow of water which contributes to siltation; block fishing routes and rotting phumdi cause a reduction in overall water quality. The dam also causes water levels to remain high year-round creating a permanent flooding situation and preventing the phumdi from sinking to the lakebed for annual nutrient retrieval. Nearly one hundred thousand people depend on the lake for their livelihood, and the phumdis plays a vital role in this equation. The phumdis are important to maintaining the ecology of the lake, and with it the economy of the state. The phumdi supports productive fisheries, provides important plant species which are used for fencing and fuel, and is critical to the maintenance of water quality in the lake. The phumdi is a good source of high-quality compost, which assists in decreasing the proliferation in the lake.

3.2.2

Applicability to Contemporary Infrastructures

Due to their natural buoyancy, the phumdi is able to support populations during water-level changes. Similar floating meadows could be used in urban water bodies to enhance natural biodiversity and natural water purification. This study also exemplifies how lakes could sustainably support large-scale, aquaculture systems. Phumdis successfully accommodate different water-level fluctuations, while supporting biodiversity and enhancing food production. However, these natural floating meadows would require salt-tolerant plant species if they were to be used in saltwater environments.

3.2.3

Ma’a Floating Taro Islets of the Puluwat (Poluwat) and Floating Taro Patches and Agroforestry System of the Yap, Micronesia

Yap is a cluster of small islands making up one of the states in the Federated States of Micronesia, a country composed of more than six hundred islands in the Pacific Ocean north of Australia.52 In a tropical climate that is humid year-round, less than one percent of this country is dryland making freshwater limited. This scarcity, coupled with frequent drought, salinity, and poor soil, has inspired unique naturebased innovations centered around the production of taro (Fig. 7).53 In Palau, another Micronesian island which cultivates Taro, it is believed that “the taro swamp is the mother of life” and women were the main cultivators.54 Marshland floating taro 52 Manner 53 Ibid. 54 Ibid.

(1980).

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Fig. 17 Taro islets at Poluwat Atoll, surrounded by the agroforest. Source Google Earth© 2020 Maxar Technologies

patches in Yap were constructed by older women and young mothers (Fig. 18), using simple tools such as sticks, and without the use of artificial fertilizer. Even so, these fields produced yields higher than commercial farms.55 The indigenous people of Yap grow taro free from chemicals, fertilizers, and machinery by creating stone lined canals and pools, hanging baskets, floating islets, floating patches, raised beds, and patches in agroforests. Requiring warm temperatures, taro is a hardy root vegetable with an edible starchy bulb and leaves that grow up to a meter that can withstand the monsoonal rains and tolerate waterlogged soil, and it is slightly tolerant of saltwater.56 The primary species grown on these islands are giant swamp taro or Cyrtosperma chamissonis (also known as Cyrtosperma merkusii), and the smaller, less salt-tolerant ‘true taro’ or Colocasia esculenta. The giant swamp taro is suited to agroforestry and marsh integration, being hardy, shadetolerant, having longevity and the ability to grow both up and down.57 While the true taro produces large yields quickly and is commonly grown on homesteads, with the ability to only grow upward, Colocasia has been interplanted with Cyrtosperma, as the Colocasia’s fast growing provides shade that hinders weeds, and the Cyrtosperma grows for longer so it is present after the Colocasia is harvested.58 While many forms of taro agriculture exist on these islands, the wetland cultivation of taro in Micronesia is explored here. 55 Nakashima

et al. (2018). and Lawrence (2003). 57 See Footnote 3. 58 Falanruw, M. C. Taro Growing on Yap. Yap Institute of Natural Science. 56 Moore

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Fig. 18 A woman repairing a ma’a on Puluwat Atoll in 1988. The woman’s pride in her taro is seen through the care and attention to details such as the woven coconut frond wrapping the islet. Source Reproduced with permission from Manner (2010)

In marshes deep in the mainland island of Yap, taro is grown in baskets, on elevated beds, or floating islets. The baskets, called kang-kong, are constructed as either bottomless, built in the patches, or hanging, held in place with sticks. Baskets are made from woven coconut fronds and are filled with mulch or good soil. The taro is planted in the basket, and the roots grow down, to the freshwater below.59 Elevated beds are also used in coastal areas to raise the taro above saltwater inundated soils, and in areas where the water is too deep. The beds are built from piling organic matter which is then covered in soil. The sides of these beds are typically held in place by woven coconut fronds or husks and supportive sticks. “Floating” islets, called ma’a, and floating patches are present on a few islands. In freshwater marshes deep in mainland Yap, patches float on slow moving water and are built out of the surrounding marsh vegetation.60 Using only a knife, reeds like Phragmites and other marsh vegetation are slashed and piled onto a bed. A ditch is then dug with a stick around the bed and cut from under to disconnect it from surrounding vegetation. Mud and silt are taken from under the mat and layered on top to cover the cut vegetation. The Colocasia and Cyrtosperma taro are planted on here and grow hydroponically atop the algae-rich mulch bed, absorbing the nutrients 59 Lopez 60 See

(2019). Footnote 59.

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Fig. 19 A diagram of the floating marsh taro patches on Yap and the taro islands on Puluwat

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Fig. 20 A ma’a seen on Puluwat Atoll in 1988. The ma’a are constructed wholly of organic materials (tree trunks and leaves) that are anchored to the bottom of the depression. Source Harley I. Manner

from the flowing water. The roots grow across the mat, and the taro corm grows either within or below it (Fig. 19).61 This system of hydroponic agriculture is comparable to the Aztec floating chinampas. “Floating” taro islets, called ma’a, are found on Puluwat (now Poluwat), an island in the Chuuk state of Micronesia, and on Ulithi Atoll. The Puluwat ma’a are oval raised beds that sit in freshwater pools in the island’s interior swampland and appear to float (Fig. 20). A depression is either found or excavated, and then coconut and pandanus trunks are vertically inserted into the bottom as piles, before being covered with decomposing vegetation. The sides of the bed are surrounded by woven coconut fronds and propped by sticks, acting as a retaining wall. These islands are about one meter high, with soil sitting half a meter above the water table, and on this they grow both Colocasia and Cyrtosperma.62 The island sits in the center of the depression, where the water is deeper and less saline, and is surrounded by natural vegetation as protection from salt spray and storm waves (Fig. 19). The islets on Ulithi are constructed in a similar way, except triangular in shape rather than oval.63 61 See

Footnote 63. Footnote 56. 63 Morrison et al. (1994). 62 See

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Outside of the marshes, taro is also a major part of the agroforestry system on Yap. Subsistence agroforestry is very productive, providing food, resources, and ecosystem services such as filtering air and water, preventing erosion, and preserving biodiversity.64 The agroforest on Yap was part of a three-part system which dominated the landscape: tree gardens, open gardens, and taro patches. In this system, the tree garden’s canopy protects the soil from rain-induced erosion, and the decomposing fallen leaves provide nutrients for the soil.65 Small areas were cleared throughout the agroforest through shifting cultivation, or the practice of burning to clear an area for new crops, which revitalized soil fertility and worked as an insecticide and herbicide. Breaking the canopy and forming “skylights,” these open gardens were planted with yams and other crops.66 These gardens and taro patches were integrated in a series of ditches and raised beds. In the open canopy gardens, ditches were built alongside them to provide drainage and separate the crops from weed’s roots.67 These ditches travelled downstream to low-lying areas where they were widened for a series of connected taro patches with raised land built up next to them where crops could be planted. Earth excavated from the patches was also used for raised land on which houses and paths were built. These paths travel across the island and are paved with shells, coral, and sand which allows them to dry off instantly after a rain event.68 The multitude of ways in which taro was grown on these islands are many ways in which agriculture was successful in the presence of saline soils and little space. Traditional taro cultivation understood the interface of freshwater and saltwater. This is also evidenced by the Mu’ut: taro patches near the sea that were lined with rocks to prevent saltwater intrusion from below while they received freshwater from rain-fed channels.

3.2.4

Applicability to Contemporary Infrastructures

Innovations like the mu’ut, the ma’a,, and the other taro cultivation methods could be revived as a system for resilient coastal agriculture based upon the variations in design and plant selection in response to water salinity and nutrient needs. The Yap mu’ut, a way in which plants that require freshwater are able to be planted in saline soil, and the use of salt-tolerant species in other areas, can be explored as how to adapt agriculture to salinity intrusion from sea level rise. The use of local vegetation in many forms displays the versatility of using plants as building material. Additionally, the process of excavating soil for the creation of both irrigated planting beds and walls can be replicated. In this process, the lower areas reach the freshwater and the soil that is taken out is used to build up walls and land.

64 The

Environmental Literacy Council (2015). and Ruegorong (2015). 66 Falanruw et al. (1987). 67 Conrad and Newell (1992). 68 See Footnote 3. 65 Falanruw

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Fig. 21 This world map indicates the location of the two indigenous technologies that are analyzed in this section

3.3 Offend/Advance Advance is a strategy that has a complex history of working against ecosystems. Advance is a relatively new sea level rise response strategy to the IPCC, coming to the forefront now due to land scarcity and population growth. This strategy refers to the expansion into the water by creating new land with land reclamation or by the use of dikes.69 The filling of wetlands and coastal ecosystems with sand and fill on which to build is an example of this present in many coastal cities. For example, through the historic use of “advance” in China, about fifty percent of coastal ecosystems have been lost, leading to a range of impacts such as loss of biodiversity, decline of bird species and fisheries resources, reduced water purification, and more frequent harmful algal blooms.70 This strategy has potential to not only destroy protective ecosystems, but actually enhance erosion and grow the coastal floodplain, and so it must be implemented with careful consideration for the ecosystem it inhabits.71 In the following section, the Mulberry Dike and Fish Ponds in Huzhou, China, and the Asi artificial islands of the Malaitan on Langalanga Lagoon on Malaita, Solomon Islands, are explored as infrastructures that combine the creation of new land with the creation of ecosystems (Fig. 21). Rather than creating new land through

69 See

Footnote 2.

70 Ibid. 71 Ibid.

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Fig. 22 Mulberry dike and fish pond structures at Huzhou, China. Source Google Earth© 2020 CNES/Airbus

filling ecosystems with foreign materials, these examples expand the materials and services provided by these ecosystems, rather than destroying them.

3.3.1

Mulberry Dike and Fish Ponds in Huzhou, China

The planting of mulberry trees and sericulture, or the rearing of silkworms, began in China over five thousand years ago. The mulberry dike and fish pond system is two and a half thousand years old and integrates this process with fish, livestock, and dikes, called tanglu (Fig. 22). Several agricultural production modes working in symbiosis create this complex multi-dimensional eco-agricultural system. The system also functions as part of a larger-scale reservoir for water storage, flood regulation, and drought mitigation.72 This sustainable closed-loop system incorporates renewable energy, water management, nutrient recycling, and food production through cropping, mulberry tree growing, silkworm rearing, and livestock and fish cultivation (Fig. 23). Mulberry trees grown on the banks of the fish ponds are the first level in the system. Mulberry tree cultivation provides leaves for silkworms to eat; the silkworm feces and sloughs fall into the adjacent pond providing feed for fish; the fish feces, along with the unconsumed silkworm and mulberry waste, are then decomposed by aquatic microorganisms which produce nitrogen, phosphorus, and potassium, finally returning to the mulberry tree as nutrient-rich manure and beginning the cycle over 72 The

People’s Government of Nanxun District (2017).

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Fig. 23 Fish ponds with the city of Shenzhen in the background. Fish ponds are also used by farmers in the Pearl River Delta. Source Earnest Tse

again.73 The fish species are chosen by which level they reside in the water, a key detail that contributes to maintaining the biological balance of the pond ecosystem. The silver carp lives in the upper water, eating phytoplankton; the bighead carp lives in the middle of the water, eating zooplankton; the grass carp lives in the middle and lower areas of the water, eating water plants and vegetation; and the black carp lives in the bottom of the water, eating snails and mollusks.74 Algae and aquatic plants, such as water hyacinth (Eichhornia crassipes), grow in the pools and are controlled through consumption by the grass carp. These plants produce oxygen and glucose, adding nutritional benefits to the fish and indirectly the manure and mulberry trees (Fig. 24).75 The fish ponds are an element existing within a larger irrigation, drainage, and flood prevention system. In Huzhou, the northern area of the region lies in the Yangtze River Delta in the lowland south of the Taihu Lake, one of the largest freshwater lakes in China, and was vulnerable to flooding.76 In response to this, the Zong Pu Heng Tang system of irrigation and drainage integrated existing and formed rivers—the wide horizontal, Hengtang, and narrow vertical, Zongpu—into a grid-like formation reaching the lake. Water is stored in the rivers and allows for gradual sedimentation, while overflow is drained to the lake. The banks of dikes within the series of ponds are 73 Gongfu

(1982).

74 Ibid. 75 Ibid. 76 Zhuang

(2018).

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Fig. 24 Mulberry dike and fish pond is a closed-loop system, in which each element provides nutrients for another

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Fig. 25 The fish pond system creates retention ponds for floodwater and dikes for protection decreasing the vulnerability to flooding

created from dredging perennially flooded depressions in the earth, and digging the mud from the fish ponds to the banks on which the mulberry trees are planted. This increases the dike height and water storage capacity, improving flood resilience.77 This is also the case for the fish ponds at the Pearl River Delta near Shenzhen, as the swamplands were converted into the fish pond landscape (Fig. 25)78 .

3.3.2

Applicability to Contemporary Infrastructures

There are numerous additional benefits from each element of this system, beyond being integral to creating a closed loop. The system maximizes use of local resources and produces commodities (fish and silk), which in turn provide income and employment (Fig. 26). The nutrient-rich mud created in this system is used as both fertilizer and a building material for flood mitigation. It is the result of recycled waste and energy, which replaces the need for chemical fertilizers, pesticides, herbicides, and concrete flood barriers, while cutting costs and creating a zero-emission system. Additionally, the mulberry tree is a great air purifier and can sequester carbon more effectively than most agricultural plants.79 This integrated system of water and land resources forms a resilient and effective closed-loop, hybrid solution that can inform both water and land management practices, agriculture, sericulture, and aquaculture, in areas that experience frequent flooding. To develop this system within dense urban areas would require the reintroduction of these activities within the urban landscape

77 Ibid. 78 Marks 79 See

(2011). Footnote 77.

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Fig. 26 The mulberry tree leaves grown on the dikes of the fish pond generate food for silkworms, creating an integrated, sustainable system of fish farming and silk production. Source Reproduced with permission from Okic (2020)

and an allowance for floodable zones within the public domain to accommodate aquaculture ponds.

3.3.3

Asi Artificial Islands of the Malaitan on Langalanga Lagoon on Malaita, Solomon Islands

Langalanga stretches north to south along twenty kilometers of Malaita’s western coast in the Solomon Islands. The saltwater people who live on the long and narrow Langalanga Lagoon were originally refugees from the mainland. However, researchers argue that the saltwater people started creating the artificial islands fifteen generations ago which is around three hundred years.80 Today fifteen Asi islands exist, with some of the islands being entirely artificial while others are artificial expansions of natural islands (Fig. 27). These range in size from one thousand square meters to approximately one hundred and twenty thousand square meters, which is the largest and is known as Laulasi Island. It has been estimated that almost twelve thousand Malaita people in the Langalanga Lagoon live on the artificial islands,81

80 Nunn

(2009). (2010).

81 Glemarec

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Fig. 27 Multiple artificial islands at Langalanga Lagoon. Source Google Earth© 2020 CNES/Airbus

with ten to fifteen families living on some, while on others a lone house stands above the waves (Fig. 28).82 To build the islands, stones are carried to a desired location using a log raft. Rafts were placed at the island perimeter to designate the island construction zone. Afterward, they were weighted and sunk using local coral stone. Coral stones were then layered until their surface was above the high tide and then filled with fine, coral rubble and soil to cover the holes and level the new land.83 The soil was gathered from the river, the beach, or the reef, and it was transferred to the island.84 At the top, they would plant trees to bind together the coral stones (Fig. 29). A specific tree known as Alu exists on every island, and is used mostly for shade, while coconut and lettuce trees on the islands are used for food production. At some islands, Barringtonia trees exist as well.85 To ensure island durability, the first rock would be placed by the kastom priest to secure the power of the shark, which is believed to be reincarnations of dead ancestors who protected their descendants. Upon completion, a rock from the first clan’s island was laid to ensure that the ancestors will protect the Asi.86 Two differing theories are recounted to explain the existence of the islands. Firstly, they were built as protection from enemies,87 and secondly to escape from the

82 Tuwere

(2010). (2001). 84 Walter (1930a). 85 Walter (1930b). 86 Guo (2015). 87 Ibid. 83 Guo

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Fig. 28 Langalanga artificial island and a traditional house construction. Source Reproduced with permission from Scaruffi (2011)

Fig. 29 Construction phases for the artificial islands

malaria epidemic.88 At the ocean side of the lagoon, reefs and mangroves protect the lagoon from strong waves. Shallow waters, combined with materials from coral reefs, and high biodiversity, created the perfect environment for the construction of artificial islands. Islands were initially built for the size of a family. Later on, they 88 Bryant-Tokalau

(2011).

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Fig. 30 An axonometric and a section of the artificial islands. The houses are usually found on the perimeter, revealing in this way a vacated space in the middle that is used by the community for gathering. The houses are raised to protect from the water during high tides

would expand to accommodate more families. Multiple dwellings were added on the perimeter, forming a central public space for communal activities such as dancing and playing.89 The houses were placed on stilts to accommodate water during high tides. For the Langalanga residents, high tides are a natural and welcoming phenomenon. When population and infrastructure density grew, houses were built with two stilts on the island and two in deeper water with additional landing spaces for canoes. One side of the island was often built at a higher elevation for the residents to be able to fish (Fig. 30).

89 See

Footnote 86.

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3.3.4

Applicability to Contemporary Infrastructures

These islands are an example of how local resources can be used to create permanent and vegetated land in a lagoon environment. At the same time, it is important to notice the scale of the islands. These small-scale islands required less materials for the construction, protecting in this way the environment from overexploitation and allowing at the same time the natural flow of water. Moreover, the indigenous people, after observations, were able to accommodate both high tides and low tides into their design. As mentioned earlier, the islands are built above high tide levels, creating in this way a layer of protection. The plantation on the side of the ocean was also protecting the islands from storms. In addition, houses were elevated to provide an extra layer of protection in case of extreme events, whereas, during low tides, residents were able to walk to the islands. In summary, the analysis of Langalanga artificial islands provided an important insight for the expansion of land in the water that adapts to the environment and people’s lives.

3.4 Retreat The final scenario of managed retreat will literally mean moving in a different direction. This is a discussion happening most commonly within the circles of scientists, planners, activists, and academics about adapting to climate change by moving out of risk zones and back to higher ground. This strategy does not primarily consist of a physical infrastructure, but rather involves political and social realignments, which are impeded by high upfront costs.90 Retreat is the strategy employed when all the other adaptation methods have failed to protect a coastal area. The IPCC defines retreat as the strategy of protecting people by moving them away from the natural hazard which can be further divided into: migration, the voluntary movement of people; displacement, or resettlement, which is the involuntary and unforeseen movement of people; or relocation, which is managed realignment.91 In the following section, the Relocation of the Biloxi-Chitimacha-Choctaw, on Isle de Jean Charles, Southern Louisiana, is explored as the way in which indigenous people have interacted with this final strategy.

3.4.1

Relocation of the Biloxi-Chitimacha-Choctaw, on Isle De Jean Charles, Southern Louisiana

Since 1930, Louisiana’s coastal plain has lost more than five thousand square kilometers, approximately ninety-eight percent of land, to the waters of the Gulf of Mexico 90 Nonko 91 See

(2020). Footnote 2.

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Fig. 31 Remains of the Isle de Jean Charles and the one road that connects the island with the region. Source Google Earth© 2020 Terrametrics

(Fig. 31). Isle de Jean Charles, the historical homeland of the Biloxi-ChitimachaChoctaw Indians of Southern Louisiana, is the most profound example of the state’s vanishing coast. The narrow island in the bayous of South Terrebonne Parish, Louisiana,92 has been plagued by a host of environmental problems that have led to increasing flood risk. Unprecedented soil subsidence has led to the once-wooded landscape’s slow disappearance into the sea, making the Biloxi-Chitimacha-Choctaw Indians of Southern Louisiana, America’s first climate refugees. This has been exacerbated by the lack of soil renewal resulting from the construction of levees that separate the river and the rising sea, and the thousands of oil and gas canals dredged through surrounding marshland that have caused saltwater intrusion, and coastal erosion (Fig. 32). Two years after receiving federal funding to move to higher ground, the tribe remains in a landscape slowly subsiding as they wait for new homes.93 When the Biloxi-Chitimacha-Choctaw Indians arrived in the area in the early 1800s, they settled on the highest ridge, located on Isle de Jean Charles. Even though the Isle de Jean Charles was considered uninhabitable swamp land, in 1876 the State of Louisiana began selling the land to private individuals, at a time when it was illegal for a Native American to purchase land.94 However, the first foreign settler, Jean Marie Naquin, a Frenchman, married Pauline Verdin, a Native American. The 1880 Terrebonne Parish Census listed the first land buyers as residents and included just four families, all descendents of the first settlers who had married 92 Tribal

Government (2019). (2018). 94 See Footnote 100. 93 Jackson

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Fig. 32 A home on the island that was destroyed by flooding. Source Apricot (2007)

Native Americans.95 By the census of 1910, the area was officially called “Isle á Jean Charles” and had grown to sixteen families, all descendants of the first four families, and totaling seventy-seven people, whose occupations included fishermen, oystermen, or trappers. For the last nearly ninety years, the Southern Louisiana wetlands have been collapsing due to subsidence. In 1928, the Flood Control Act authorized the building of levees to keep the Mississippi River within its banks, which has prevented sediment-laden spring floods from replenishing the marshes. For millennia, the river has been building land as the gulf retrieves it. Now, without the sediment, it is a battle between the gulf and gravity, with climate change and sea level rise worsening the circumstances. In 2002, the Morganza to the Gulf Flood Protection System was built by the Army Corps of Engineers to protect communities along the Louisiana coast, but the system was built to pass north of the Isle de Jean Charles determining it was not costeffective to include the island. In January 2016 after seventeen years of negotiation, the community was awarded a first-of-its-kind forty-eight million dollar relocation grant from the U.S. Department of Housing and Urban Development (HUD), worked out by the Louisiana State Office of Community Development and tribal leaders.96 95 Cottage 96 Ibid.

Films (2014).

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For the Biloxi-Chitimacha-Choctaw Indian, land use decisions combined with climate-induced displacement have threatened both unity and sovereignty. Furthermore, as place is the foundation of their way of life, the loss of land has led to depletion of traditional practice and cultural assets. As the relocation process begins, disputes about the original terms of negotiation have arisen as islanders insist the original relocation plan was not presented honestly. They say they were told that if they accepted a new home in the resettlement, they would be allowed to retain ownership and access to their Isle de Jean Charles lands—and the structures built there—that have been part of their tribe’s heritage for two centuries, but instead this buyout of their ancestral lands would forfeit their say in protecting them.

4 Futures Sea level rise and climate change is an unprecedented adversary, one that is adaptive, responsive, and capable of complex interactions along coastlines. Variations in local conditions, communities, and ecosystems coupled with global weather patterns will warrant unique responses, amplifying strengths and counteracting weaknesses. Increasingly in post-disaster scenarios, water is being cast as a menacing and unpredictable force to be mastered by building hard, fortifying infrastructures. Across the globe, homogeneous, single-purpose, high-tech strategies are being deployed irrespective of local communities and conditions, with structures and materials that are incompatible with local ecosystems. This chapter counters this narrative, documenting indigenous systems that have been independently simultaneously evolved in response to sea level rise and climate change. These responses have catalyzed cultural, ecological, economic, agricultural, and climate resilience using local, multi-ecosystem applied nature-based technologies. The IPCC Special Report on the Ocean and Cryosphere in a Changing Climate from 2019 found that “in practice, hard, sediment-based, and ecosystem-based protection responses are often combined and there is high agreement that such hybrid approaches are a promising way forward.”97 Indigenous innovation has proven, over years of adapting to coastal resiliency, nature-based hybrid approaches are effective. The individual indigenous innovations documented in this chapter exhibit the potential of alternative nature-based technologies of indigenous peoples that have yet to be explored as climate mitigating technologies. In developing this compendium and exhibited in the comparative case studies in this chapter, the phenomenon of simultaneous innovation repeatedly occurs. Simultaneous innovation, which suggests a universal typology in response to a crisis, in the context of indigenous nature-based technologies is described by Watson in Lo-TEK, Design by Radical Indigenism as, “Other unknown cases of simultaneous innovation [that] have emerged in isolated indigenous communities who confront similar environmental constraints.” Across the Pacific, indigenous innovations stretching from forest to foreshore, like the 97 See

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ahupua’a of Hawaii, the vanua of Fiji, the subak of Bali, and the derderin of Australia, simultaneously evolved as cooperative land management systems. These systems cultivate foods, building materials, medicines, and firewood, while regulating coastal protection, biodiversity conservation, and integrated ecosystem management. A unique technology of the vanua and the ahupua’a are the intertidal aquaculture ponds. Although these are each designed independently and distantly, they also resemble the derdernin ponds of Australia.98 This observation indicates there is ancient knowledge about an optimal response to climatic extremes that could evolve new climate mitigating strategies. These soft, green, living systems further optimize their symbiotic relationships and reduce their ecological impacts by using biodiversity as a building block composed of local materials and traditional ecological knowledge. Many of these technologies exist in combination as a multi-ecosystem scenario, incorporating multiple technologies that range across a land to sea interface, from underwater ecosystems at low elevation to terrestrial ecosystems at high elevations—whether that be a wall that functions as an ecosystem, wave break, and anti-erosion strategy while providing subsistence fishing needs, such as the Ahupua’a Loko’lai, or a land reclamation technology that utilizes raised, habitable, productive land on a lacustrine environment, such as the Asi Artificial Islands. The resilience of these isolated technologies increases in combination with multiple complementary systems, as has been done for millennia by indigenous communities.

4.1 Hybridizing Ecosystem-Based Approach is the Best Scenario for Infrastructural Resilience Incorporating a mix of adaptive scenarios, including defend, surrender, and offend, these multiple complementary systems are more resilient. Embedding nature-based technologies within ecosystems such as reefs, mangroves, saltmarshes, dunes, rivers, and wetlands amplifies the numerous co-benefits of each technology and offers multiple nested scales of resilience. A significant hybrid example analyzed previously is the Asi artificial island of the Langalanga Lagoon, which utilizes existing reef and mangrove ecosystems with an accommodative infrastructural approach. In the Langalanga Lagoon, a natural reef located at the perimeter of the lagoon composes the first layer of protection, and mangroves then offer a second layer of protection. The finished level of the constructed island above high tide is the third layer, followed by the raised stilt housing which generates the final layer of protection (Fig. 33). Similar to this, the Derdernin and Ngurruwarr Fishing Traps of the Lardil and Kaiadilt of the South Wellesley Islands, Australia, utilize both mangroves and reefs. The root systems of mangroves assist in stabilizing the rock wall fish traps by intercepting tidal force. In addition, reefs found at the ocean side of the fish trap were protecting the rock wall from strong waves, while increasing the biodiversity of the 98 Watson

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Fig. 33 Ecosystem section of the Langalanga artificial island

area as a reef ecosystem habitat. Moreover, the design of the rock wall took into consideration the strong winds and the tidal forces to determine the best placement for the openings for the fish and the water circulation. Oysters additionally contribute to the protection of the system both by producing calcium carbonate which binds the rocks together and by increasing the biodiversity of the area. At the same time, oysters need the rocks in order to attach and develop, creating in this way a system of symbiosis. The tide was also used as the mechanism for catching fish in the traps, as the rising tide brought the fish in and caught them as it fell. This utilization of the naturally occurring tidal flow required no additional energy input and was predictable and relied upon as a food source especially when storm events disrupted land-based agriculture. In the case of Wellesley Islands, the natural reefs and mangroves combined with the rock infrastructure and the oysters create a hybrid ecosystem approach. The fish ponds of the Hawaiian Islands were similar to these in the construction of coastal infrastructure for harvesting fish. The ponds were part of the larger mauka-makai (mountain-to-sea) ahupua’a socioeconomic and land use system, which divided the islands by way of the naturally occurring watershed. The fish ponds, specifically the loko i’a kalo, loko wai, and loko pu’uone, each used the watershed to feed the ponds and were positioned in different locations on the island to make use of the variations in island topography and land type. The coastal ponds, the loko pu’uone and loko kuapa, were built from lava rocks and coral and utilized a coralline alga as a cement, making use of local resources and knowledge of ecosystem services. The ahupua’a was composed of five biological resource zones: At the highest point was the cloud forest (wao akua), a sacred restricted zone; below this came the forest zone (wao nahele) which was not cultivated and provided timber, birds, and native plants; then came the agricultural zone (wao kanaka) which included upland plantings, agroforestry (wao la’au), irrigated taro patches, and a complex system of extensive terraces; and finally the coastal zone (kahakai) and the sea zone (kai) where the fish ponds were (see Fig. 3)99 . This watershed system ensured high biodiversity and efficient resource management which resulted in resilient food systems. 99 Mueller-Dombois

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The use of existing water systems is also seen in the mulberry dike and fish pond system. The system hybridizes the land building strategy of dike building with flood mitigation through implementation with existing water systems. The system dredges pond mud onto the dikes to build up the walls and increase water storage capacity. The overflow water is carried through the rivers to larger water bodies, protecting the crops and villages from flooding. The use of dredged mud also functions as a manure for the mulberry trees which grow on the dikes, the leaves of which contribute to the food chain that makes the mud so nutrient rich. The mulberry-dike system is an excellent example of how an understanding of a hybrid ecosystem can be used to create a low-energy, cost-effective, and self-sustaining system, while at the same time effectively mitigating flooding. Similar to the ahupua’a, the taro growing methods in Micronesia display an understanding of watershed hydrology and vegetation that results in an island-wide productive system. The methods in the system range from forest to coast, each being part of the larger agriculture system on Yap, built within the existing landscape. This system also is a method of land creation, as excavated dirt for taro patches produces raised land on which paths and houses are built. Other methods of taro cultivation float on water, build up to evade water, and build down to prevent salinity intrusion. These cultivation systems are successful without the use of fertilizers and machinery, but rather use nutrient flows, shifting cultivation, and low-tech methods—by means of only a knife and a digging stick.

5 Conclusion—Further Discussion For indigenous communities, the hybrid multi-ecosystem approach has effectively protected people and the environment for millennia. Indigenous people have learned to live symbiotically with their environments. While these innovations are not all direct examples of coastal resilience, the aquatic infrastructures work within the coastal environment and are multi-functional, symbiotic structures themselves. They were not intended for protection from sea level rise, but they can inform how we can build resiliency by working with the environment, rather than disrupting it further, and simultaneously provide additional services in the form of agriculture and aquaculture. Contemporary coastal cities are overdeveloped in the intertidal zone, destroying protective dunes, foreshore, wetlands, and mangrove ecosystems. Anthropogenic activity has also overexploited natural underwater defense systems, such as coral reef, sea grasses, and oyster beds leaving coastal areas unprotected. Furthermore, incompatible structures and material have polluted the oceans and affected local biodiversity. Taking inspiration from the multi-ecosystem indigenous infrastructural approaches analyzed above, this chapter argues for a holistic design approach of hybrid adaptation strategies that amplify social, ecological, economic, agricultural, and climate resilience for both the environment and all its inhabitants. Climate

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change will necessitate an alternative direction, for some communities that will eventually require a managed retreat. Addressing the political and social frameworks needed for this final scenario now is critical. We cannot go backward, fixing all of the hard infrastructures and extractive activities that have exacerbated the need for retreat, but we can go forward, rethinking and rebuilding in a way that supports the resilience of both communities and cities, addressing the inequalities and distance from nature that our current systems support.

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Julia Watson Designer, activist, and academic, Julia Watson is a leading expert on indigenous technologies and climate resilience. Her new book with Taschen, Lo-TEK: Design by Radical Indigenism is a bestseller and has been featured in The New York Times, The Guardian, Dwell, Architectural Digest, Topos, and more. Julia teaches at Harvard and Columbia University and her landscape and urban design studio focuses on rewilding. She has written for Topos, Landscape Architecture Frontier, ioARCH, Kerb, Scroope, Nakhara Journal, Water Urbanisms East and A Spiritual Guide to Bali’s UNESCO World Heritage. She’s a fellow of TED, Summit REALITY, Pop!tech, Christensen Fund, Charles Eliot, Olmsted award. Born in Australia, she regularly travels to indigenous cultures and sacred sites across the globe. Despina Linaraki Architect engineer, Despina Linaraki is a Ph.D. researcher at SeaCities, Cities Research Institute, in Queensland. She has completed a Master of Science, 2015 from Columbia University in New York, at Advanced Architectural Design and the Development of Global Cities. Furthermore, she holds a Master of Architectural Engineering, 2013 from Technical University of Crete, in Greece. Since 2014 she is a registered Architect in Greece. Having lived experience in different coastal cities around the world, she is researching nature-based solutions for the adaptation of low-lying islands and coastal cities to sea level changes and floods through the interdisciplinary of architecture with the fields of biology and geology.

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Avery Robertson is a designer, researcher, writer, and editor passionate about the intersection of the built environment and the ecological environment. She completed a Bachelor’s of Science in Architecture Studies with a focus on sustainable design before going on to obtain her Master’s in 2018 in Sustainable Urban Environments, both from Northeastern University. Her current work focuses on bringing sustainability practices and climate science to the public through design and communications.

Exploiting Sedimentand Morpho-Dynamics in Coastal Adaptation Strategies to Sea-Level Rise: A Case Study of the Vietnamese Mekong Delta Thang Viet Nguyen, Kelly Shannon, and Bruno De Meulder Abstract This chapter explores potential strategies to engage with sediment dynamics and coastal geomorphology in response to sea-level rise through a case study of the Vietnamese Mekong Delta. The delta has been formed by deposition of sediments during the last several thousand years. With a low elevation and significant land subsidence, it is among the most vulnerable deltas in the world under the impacts of climate change, sea-level rise and particularly flooding. Its entire coastline is characterized by a dynamic process of accretion and erosion. The chapter firstly provides an overview of geomorphology—concentrating on sedimentation and erosion—along the coast of the Mekong Delta, where most of the massive sediment discharge of the Mekong River is trapped on the subaqueous delta area and two-thirds of the sediment is transported southeastwards to the southernmost Ca Mau Cape. Then, the chapter draws lessons from an implemented local scale project on Vietnam’s East Sea (also referred to as the South China Sea), where bamboo fences are used to reduce coastal erosion and stimulate sedimentation. Permeable T-fences trap sediment and create calm water conditions for further deposition along the muddy coast. In turn, restoration of the eroded coastal floodplain creates preconditions for rehabilitation of the mangrove forest. Finally, the last section examines a coastal strategy, proposed in the Mekong Delta regional plan, to enhance controlled and increased sedimentation along the East Sea coast in order to drastically up-scale the natural land-gaining process, which can be further consolidated by the systematic planting of mangroves. By engaging with the complex circulation system of sediments along the coast, this strategy can initiate a new protective/productive landscape amidst a constructed ecology that will not only strengthen the ecological structure of the Mekong Delta, but also increase its resilience in the context of sea-level rise. T. V. Nguyen (B) SeaCities, Griffith University, Griffith, Australia e-mail: [email protected] K. Shannon · B. De Meulder KU Leuven, Leuven, Belgium e-mail: [email protected] B. De Meulder e-mail: [email protected] © Springer Nature Singapore Pte Ltd. 2021 J. Baumeister et al. (eds.), SeaCities, Cities Research Series, https://doi.org/10.1007/978-981-15-8748-1_5

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However, it must be noted that sedimentation in the Mekong Delta is increasingly threatened by sediment supply deficit.

1 Introduction In the context of the SeaCities project, the Mekong River Delta is an incredibly interesting case study. Since its formation, the relation of water and land has been continually shifting and given the predicted consequences of climate change, today it is an extremely vulnerable territory. The Mekong River Delta has an area of 49,500 km2 (40,604.7 km2 of which is in southern Vietnam and the remainder in Cambodia) and is the third largest delta in the world. The Mekong river, running ~4700 km from the Himalayas to the East Sea (also known as the South China Sea), is one of the largest river systems in the world, in terms of the discharge of water, as well as in terms of discharge of sediment (Hein et al. 2013). The processes of sedimentation and erosion over millennia has formed an enormous delta plain which hosts incredible fertility and biodiversity. Gradients of wetness and dryness determine occupation. Ultimately, the land is saturated with water and the water is full of land (De Meulder and Shannon 2019) (Fig. 1). With a low elevation and significant land subsidence, the Mekong Delta plain is among the most vulnerable deltas in the world under the impacts of climate change, sea-level rise and particularly flooding. A study by Minderhoud et al. (2019) concludes that the Mekong Delta plain has a mean elevation of 0.82 m, meaning that it has one of the lowest elevations of all mega deltas in the world. The tidal and coastal areas of the Mekong Delta have elevations of only 0.3–0.7 m (Balica et al. 2014). Moderate estimates of absolute sea-level rise [~40 cm by 2100 (Church et al. 2013)] may result in a quarter of the delta falling below mean sea level by the end of the century (Minderhoud et al. 2019). Minderhoud et al. (2017) also found the delta subsiding at increasing rates, with present delta-average rates exceeding 1.1 cm per year due to massive groundwater extraction. Therefore, large parts of the delta may face submersion already during the coming decades. According to Zoccarato et al. (2018), the lower Mekong Delta is threatened by permanent inundation when the rates of natural compaction of the delta plain (up to ~2 cm per year at the coastline) is no longer counterbalanced due to reduced sedimentation rates in scenarios of sediment supply depletion and sea-level rise. An important effect of the possible submersion due to subsidence is that flows of water throughout the delta, which are already slow due to very limited differences in topography, will come to a standstill in many places and consequently aggravate sanitation and water pollution issues. The Mekong Delta is naturally endowed with valuable ecological assets. Over the past three centuries, hydraulic interventions have resulted in the delta becoming a key productive region for food, sea products, fruits, flowers and tree nurseries. The hydraulic interventions turned what in essence was a quagmire into a mosaic of paddy fields, regulated by a sophisticated and immense network of canals and drains. The water system is the essence of the Mekong Delta and literally the register upon

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Fig. 1 The location of the Mekong Delta and the basin of Mekong River from Tibetan plateau. Source RUA (2016)

which everything is grafted. During the past four decades, Vietnam moved from a country which could not sufficiently feed its population, to a major exporter of aquaagriculture products. The Vietnamese portion of the delta is home to approximately 17.3 million Vietnamese inhabitants (GSO 2019) and has undergone accelerating urbanization and development. Nonetheless, it remains a predominantly agricultural region. The overall pattern of settlements in the Mekong Delta is characterized by Terry McGee’s definition of ‘desakota,’ from Bahasa Indonesian desa for village and kota for town or city (as referenced in De Meulder and Shannon 2019) (Fig. 2). The urban population in the coastal zone accounts for approximately 37% of total urban population of the Vietnamese Mekong Delta (SISP 2017). In 2020, it is estimated that approximately 2 million people live in urban settlements (as classified by Vietnamese regulations: An urban settlement has at least 4000 residents) in the coastal zone, with 18 cities/towns (i.e., urban population ranging from 50,000 to 250,000 residents) located within 40 km from the coastline (SISP—RUA 2017). These settlements are embedded within 720 km of coastline and are driven by expanding economic activities including aquaculture, energy, tourism, fishing and agriculture. It is also an area strongly influenced by the natural dynamics of the coastal environment: tide, saline intrusion, flooding, shoreline erosion and sedimentation.

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Fig. 2 Urban network in the Vietnamese Mekong Delta. Source RUA (2016)

On the other hand, coastal development in the Mekong Delta has increasingly created negative footprints on valuable ecosystems. Mangrove forests are rapidly disappearing, mostly due to land reclamation, with conversion of these important ecosystems to both shrimp ponds and agricultural fields (GIZ 2018). Sea dykes are being increasingly built along parts of the muddy East Sea and Gulf of Thailand coasts for protection from marine flooding and for shrimp farms, generating a ‘mangrove squeeze’ (Phan et al. 2015). With the regional change of sediment supply, the diminishing of mangrove belt in the coastal zone contributes to the delta’s increased vulnerability in the face of sea-level rise. Although for the last several thousand years the Mekong Delta has continually extended its shoreline seaward (~30 m per year) by sedimentation (Liu et al. 2017a), nowadays, about 377 km (i.e., more than half) of the 720 km Mekong Delta’s shoreline is eroding—with 70 km of these having extreme rates of more than 20 m of erosion annually (GIZ 2018). According to Marchesiello et al. (2019), the recent observed patterns of erosion along the Mekong Delta’s coast are due to a combination of natural and anthropogenic processes, including: natural redistribution of subaqueous sediments (due to hydro-morphodynamic processes), fluvial sediment supply deficit, land subsidence and mangrove squeeze. Karlsrud et al. (2017) and Marchesiello et al. (2019) considered that subsidence rates are particularly significant (2 cm/year) along the eastern peninsula between Bac Lieu and Soc Trang, explaining the observed shoreline retreat despite favorable sediment transport, and along the western Ca Mau peninsula (1 cm/year), explaining a regime change from slightly accreting to eroding.

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A number of factors beyond Vietnam’s boundaries, particularly upstream dams and reservoirs, are completely altering the water regimes. Volumes of both water and sedimentation loads are decreasing rather drastically. In the pursuit of fresh water, deeper and deeper wells are dug throughout the entire delta for agriculture and drinking water—resulting in the collapse of aquifers and subsidence. As a result, even larger parts of the lower Mekong Delta now lie below sea level and are increasingly prone to both flooding and drought, the impacts of global climate change and sealevel rise (GIZ 2018). Given these challenges, it is considered that ‘building with nature’ principles are beneficial in formulating coastal protection and adaptation strategies in the Mekong Delta (RUA 2016; GIZ 2018). The future of the Mekong Delta, specifically in relation to the contemporary challenges of climate change, must be grounded in an understanding of both its geology and its context-embedded cultural practices of agriculture, settlement and floodwater management (De Meulder and Shannon 2019). This chapter explores potential strategies to engage with sediment dynamics and coastal geomorphology in response to sea-level rise—concentrating on sedimentation and erosion—along the coast of the Mekong Delta. It seeks to draw lessons from an implemented project of bamboo fences to reduce coastal erosion and stimulate sedimentation and a territorial-scale coastal strategy, as proposed in the Ministry of Construction’s Revised Mekong Delta Regional Plan to 2030, Vision to 2050. The aim is to innovatively manage the decreased levels of sedimentation along the East Sea coast in order to create new protective and productive landscapes. The Mekong Delta’s shallow continental shelf, which depends on, and has an effect on, seabed sediment composition and accumulation patterns, provides yet untapped opportunities for transportation, aquaculture, mining, fishery and tourism (RUA 2016).

2 Overview of Geomorphology Along the Coast of the Mekong Delta 2.1 Sediment Accumulation and Formation of the Mekong Delta Most of the Mekong River’s sediment originates from the Himalayan highlands. Volumes of sediment are transported over ~4700 km in river systems and most of the sediment reaches the ocean as fine silt and clay (i.e., muddy sediment finer than 64 µm) with some sand trapped in shallow coastal settings (Nittrouer et al. 2017). Milliman and Syvitski (1992) estimated the annual sediment load was ~160 million tons in the pre-dam era. According to Liu et al. (2017a: 73), ‘sediment accumulation in the past 7500 years has built the Mekong Delta ~220 km seaward and formed ~50,000 km2 of subaerial surface and 11,000 km2 of modern subaqueous delta. The long-term average shoreline growth rate has been ~30 m per year, and the net land gain rate has been 7 km2 per year. Mekong-derived sediment has also accumulated

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along the shelf to the southwest, forming a > 200 km long mud-dominated deltaic coast. Most subaqueous delta deposition has occurred within the last ~1000 years.’ The present-day Mekong Delta has been shaped by sedimentation over the time scale of millennia (as shown in Fig. 3), resulting in a broad, asymmetric subaerial delta plain bounded by a long, narrow subaqueous delta clinoform—the region of greatest sediment accumulation in the deltaic system (Eidam et al. 2017). An asymmetric progradation process implies the southwestward sediment transport and reflects an increased wave influence (Li et al. 2017). The offshore portion of the Mekong Delta rests on a very shallow and gently sloping (1:15,000) continental shelf (Liu et al. 2017a).

Fig. 3 Map of the Vietnamese Mekong Delta showing the main depositional paleoenvironments. Source Zoccarato et al. (2018), https://creativecommons.org/licenses/by/4.0/

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2.2 Subaqueous Delta and Longshore Sediment Transport The Mekong River discharges into the East Sea and forms a subaqueous deposit known as a clinoform (Nittrouer et al. 2017). It is estimated that 80% of the sediment discharge of the Mekong River into the East Sea is trapped on the subaqueous delta area (Xue et al. 2012). This subaqueous delta clinoform, which extends >300 km along the inner shelf adjacent to the Mekong Delta, has a shallow topset region (20 m deep) (Nittrouer et al. 2017, Liu et al. 2017a). Most of the sediment remaining in the ocean accumulates on the inclined foreset region at local rates of >10 cm per year (Nittrouer et al. 2017). According to Eidam et al. (2017), the Mekong clinoform is distinguished among large river deltas in that the transition (or subaqueous ‘rollover point’) between the broad, flat topset and steeper foreset lies at a depth of only 4–6 m, while for many large river deltas, the subaqueous rollover depth is commonly located at 25–40 m depth. While approximately one-third of the Mekong’s sediment accumulates near the mouths of the Mekong’s distributary channels, two-thirds of the Mekong’s sediments accumulate in distal areas extending to the Ca Mau Peninsula and beyond (Nittrouer et al. 2017), as a result of sediment transport along the coastline to the southwest and to the southernmost spit of Cape Ca Mau (Xue et al. 2010). The Mekong Delta, classified as a mixed-energy system (wave- and tide-dominated), is affected by two different circulation systems: to the east is the southern East Sea, characterized by a regular semi-diurnal tide with 3.5 m tidal range; to the west is Gulf of Thailand, characterized by an irregular diurnal micro-tide with 0.8–1.0 m tidal range. The shelf current is controlled by the monsoon regime. For the East Sea, currents shift direction twice annually during May (from southwestward to northeastward) and October (from northeastward to southwestward). Current velocity along the Gulf of Thailand side is much smaller than along the East Sea, in both northeast monsoon and southwest monsoon seasons (Xue et al. 2014). There is wave-driven sediment transport for the Mekong-derived sediment: during the high river discharge season (May–October), a considerable part of riverine sediment is delivered to the Mekong River mouth and temporally deposited there; during the low river discharge season (November–April), previously deposited sediment is resuspended by strong mixings associated with the strong northeast monsoon and subsequently transported southwest along-shelf by coastal circulation (Xue et al. 2014). According to a model of suspended sediment transport in the Mekong Delta by Manh et al. (2014), the sediment load entering the coast from the Mekong River was 42–50 million tons per year in the period 2009–2011. Modelling suspended sediment dynamics on the subaqueous delta by Thanh et al. (2017) demonstrates that in the high river flow season, 90% of the annual sediment volume is discharged and mostly deposited in front of the river mouths. During the low river flow season, much less sediment is exported from the river; however, the alongshore sediment transport rate is nine times higher than the sum of riverine sediment outputs, due

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Fig. 4 Simulated sediment concentration in the surface layer of spring tide in the high flow season (left) and in the low flow season (right). Source Thanh et al. (2017)

to wave and seasonal current-driven process of resuspension of the sediment layer previously deposited in the high discharge season (see Fig. 4). It is estimated that between 40 and 66% of Mekong-derived sediment is transported southwestwards by the strong seasonal monsoon-derived currents and tidal currents (Unverricht 2014; Liu et al. 2017a, b).

2.3 Shoreline Erosion and Sediment Supply Reduction The shorelines of the Mekong Delta alternately prograde and erode, both in space and time (Ogston et al. 2017). However, erosion trends along the Mekong Delta coast are accelerating, with erosion occurring over about half of the entire coastline (Anthony et al. 2015). Li et al. (2017) divided the Mekong shoreline into four categories: increasing accretion (17% of total shoreline length), decreasing accretion (36%), increasing erosion (28%), and decreasing erosion (19%). Through a study of the past 43 years of Landsat images, Liu et al. (2017a) indicated that the mode of sedimentation in the delta shifted, starting in 2005. In their study, from 1973 to 2005, the Mekong Delta’s seaward shoreline growth decreased gradually from a mean of 7.8 to 2.8 m per year; from 2005, it became negative, with a retreat rate of −1.4 m per year. Thus, suggested by Liu et al. (2017a), in about 2005, the subaerial Mekong Delta transitioned from a constructive mode to an erosional (or destructive) mode. This notable shift was coincident with the onset of river damming, and since 2006, the Mekong Delta’s subsidence rate has increased (Minderhoud et al. 2017). Liu et al. (2017a) inferred that dam construction and land subsidence might be major contributors to delta erosion. Anthony et al. (2015) argue that a decreasing river sediment supply to the coast is the prime cause of erosion, and most likely due to

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both existing dam retention of sediment and to massive channel-bed sand mining in the delta, an activity on the increase over the last decade. Subsidence accelerated by groundwater extraction is highest along parts of the muddy East Sea coast which is most severely affected by erosion (Anthony et al. 2015). Anthony et al. (2015) suggest that seasonal to persistent depletion of mud along the muddy East Sea and Gulf of Thailand sectors of the delta’s coast results in less wave energy dissipation, and, consequently, in shoreline erosion. It is evident that with the construction of more dams, uncontrolled sand mining, delta subsidence, increasing storms and sealevel rise, the Mekong Delta will likely face more destructive changes, with regard to erosion of both coastlines and underwater deposits (Liu et al. 2017a). The formation and progradation of the Mekong Delta have resulted from sediment accumulation, and sediment supply is vital for the survival of the delta in the conditions of land subsidence and sea-level rise. However, many studies have shown a decreasing discharge of sediment from the Mekong River in the past three decades (Tamura et al. 2020). Milliman and Farnsworth (2011) reported that the sediment discharge decreased to 110 million tons per year as a result of dam construction in the basin, compared to the pre-dam estimate of 160 million tons per year (Milliman and Syvitski 1992). According to Liu et al. (2017a), more recent estimates for post-dam sediment discharge vary from less than 67 million tons per year to 145 million tons per year. Based on hydrodynamic surveys in the lower distributary channel of the Mekong, Nowacki et al. (2015) suggested that sediment discharge could be as low as ~40 million tons per year from the entire Mekong River to the East Sea. (Table 1) This reflects the impacts of sharply increased human activities in the river basin, such as upstream dam construction and sand mining (Anthony et al. 2015). The rates of sediment accumulation on the inner shelf will be affected by sediment supply reduction (Allison et al. 2017). In summary, the overview of geomorphology along the coast of the Mekong Delta reveals that long-term sedimentation has formed its progradation seaward. Its mud-dominated subaqueous delta has a broad shallow flat topset region (